WO2023127152A1

WO2023127152A1 - Optical device and inspection method

Info

Publication number: WO2023127152A1
Application number: PCT/JP2021/048971
Authority: WO
Inventors: 尚憲北; 正範荒井
Original assignee: 株式会社ニコン
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2023-07-06

Abstract

Provided is an optical device for inspecting a to-be-inspected surface having a riblet structure in which a plurality of protruding portions that extend in a first direction are provided in a second direction intersecting the first direction. This optical device is configured so as to comprise: a condensing optical system that irradiates light from a light source onto an irradiation region on the to-be-inspected surface and condenses light reflected by the irradiation region; and a light-receiving element that has a light-receiving surface disposed on a surface, of the condensing optical system, different from a surface conjugate to the to-be-inspected surface, and detects the intensity distribution by using the light condensed by the condensing optical system.

Description

Optical device and inspection method

The present disclosure relates to optical devices and inspection methods used to inspect object surfaces having riblet structures.

Conventionally, the configuration of an inspection apparatus for inspecting the quality of microstructures has been proposed (see Patent Document 1, for example).

U.S. Pat. No. 8,842,271

An optical device according to the present disclosure is an optical device for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction that intersects the first direction. A condensing optical system that irradiates the irradiation area on the surface to be inspected with light and collects the light reflected by the irradiation area, and the condensing optical system is arranged on a different surface from the surface that is conjugate with the surface to be inspected. a light-receiving element having a light-receiving surface and detecting an intensity distribution of light condensed by the condensing optical system.

An inspection method according to the present disclosure is an inspection method for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction that intersects with the first direction. irradiating the upper irradiation area with light, condensing the light reflected by the irradiation area due to the irradiation of the light with a condensing optical system, and a surface different from the surface conjugated with the surface to be inspected with respect to the condensing optical system , receiving the focused light and inspecting the riblet structure based on the results of the receiving.

FIG. 4 is a schematic diagram illustrating irradiation of light onto the surface of an object having a riblet structure; It is a figure explaining a riblet structure. FIG. 4 is a diagram for explaining reflection of light on the surface of an object having a riblet structure; 1 is a schematic diagram showing the configuration of an optical device; FIG. FIG. 4 is a schematic diagram illustrating light collection by an optical member arranged closest to an object surface in a light collection optical system; It is a figure showing the projection relationship in a condensing optical system. It is a schematic diagram which shows 1st light reception data. It is a schematic diagram which shows schematic structure of a computer. 3 is a functional block diagram of a processor included in the computer; FIG. It is a figure which shows the ratio of the light quantity of the 1st reflected light in 1st light reception data, and a 2nd reflected light. It is a schematic diagram which shows the 2nd light reception data. 10 is a flow chart of inspection processing of riblet structure. 4 is a flow chart of the riblet structure measurement process.

The optical device and inspection method of the present application will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the outline of light irradiation on the surface of an object having a riblet structure, and FIG. 2 is a diagram for explaining the riblet structure.

In this embodiment, the optical device 1 is positioned at a predetermined distance from the object surface OS on which the riblet structure is formed, and inspects the object surface OS by irradiating the irradiation area IR on the object surface OS with light. For convenience of explanation, the case where the optical apparatus 1 is used for inspecting the riblet structure (object surface OS) will be described below, but the optical apparatus 1 is also applied to the case of measuring the riblet structure (object surface OS). be able to. For the sake of explanation, FIG. 1 shows a state in which the optical device 1 is arranged at a position spaced apart from the object surface OS by more than a predetermined position. Note that the object surface OS may be an envelope surface including ridges of a plurality of riblets, or may be the surface of the object before the riblet structure is formed. The object surface OS may also be referred to as a work surface.

By forming the riblet structure on the object surface OS, it is possible to reduce the frictional resistance between the object surface OS and the fluid in contact with the object surface OS. However, if the shape of the riblet structure changes, the effect of reducing the frictional resistance between the object surface OS and the fluid may decrease. Accordingly, there is a need for an optical apparatus for conveniently inspecting the shape of riblet structures on an object surface OS. At least part of the object surface OS can be said to be the surface to be inspected. At least part of the riblet structure formed on the object surface OS can also be said to be a surface to be inspected. Note that the fluid that contacts the object surface OS may be gas or liquid.

On the object surface OS, a plurality of convex portions C are provided in the second direction D2 so as to protrude from the outside of the object and extend in the first direction D1. The second direction D2 is a direction intersecting the first direction D1, for example, a direction orthogonal to the first direction D1 along the object surface OS. A convex portion C is not provided in the region R of the object surface OS. The region R can also be said to be a region between the adjacent convex portions C spaced apart in the second direction D2 on the object surface OS. The riblet structure can also be said to be a structure including the convex portion C and the region R. In addition, the riblet structure can also be said to be a structure in which only the convex portion C is formed. In addition, the convex portions C adjacent to each other along the second direction D2 may be adjacent to each other. That is, the region R may be omitted.

The riblet structure (object surface OS) may be formed by removing portions other than the convex portion C from the surface of the workpiece (eg, metal) by, eg, laser processing. Also, the riblet structure (object surface OS) may be formed by fixing (eg, adhering) a resin film (eg, UV curable resin) on which the riblet structure is formed on the surface of the workpiece. The riblet structure may be formed by applying a curable material (eg, a UV curable resin) to the surface of the workpiece and pressing a mold having a shape corresponding to the riblet structure against the layer of material on the workpiece. Although FIG. 1 shows an example of the object surface OS in which the riblet structure is formed on the surface of the work which is flat, the surface of the work may be curved. When forming a riblet structure by pressing a mold against a material layer on a workpiece, the optical device 1 inspects and/or measures the mold pressed against the material layer (for example, the shape of the mold on the side pressed against the material layer). may

The convex portion C has a pair of inclined surfaces T1 and T2 (hereinafter collectively referred to as "inclined surfaces T") inclined with respect to the third direction D3. A third direction D3 is a direction orthogonal to the first direction D1 and the second direction D2, and is, for example, a normal direction of the object surface OS. Here, in terms of design, the inclined surface T1 and the inclined surface T2 are assumed to be symmetrical with respect to the third direction D3. That is, the angle formed by one inclined surface T1 with the region R and the angle formed by the other inclined surface T2 with the region R are equal in design. It can also be said that the designed inclined surfaces T1 and T2 are symmetrical with respect to the third direction D3. Note that the designed inclined surfaces T1 and T2 may be asymmetrical with respect to the third direction D3. The third direction D3 may be a direction intersecting the first direction D1 and the second direction D2.

The interval P between the plurality of convex portions C provided in the second direction D2 may be 100 μm, for example. The size (height H) of the convex portion C in the third direction D3 may be, for example, 50 μm. The pair of inclined surfaces T1 and T2 may be inclined, for example, by ±22.5° with respect to the third direction D3, and the apex angle A of the convex portion C may be, for example, 45°. In addition, the interval P of the convex portion C, the size (height H) of the convex portion C in the third direction D3, the inclination angles of the inclined surfaces T1 and T2 with respect to the third direction D3, the apex angle A of the convex portion C is not limited to the above numerical values.

An object surface having such a riblet structure is disclosed in, for example, US Pat. No. 8,444,092, US Pat. No. 9,656,743, US Pat. US Patent Application Publication No. 2013/0146217, US Patent Application Publication No. 2016/0271930, US Patent Application Publication No. 2020/0263704, US Patent Application Publication No. 2021/0054859 described in the book.

FIG. 3 is a diagram explaining the reflection of light on the object surface OS.

Incident lights IL1, IL2-1, and IL2-2 incident in parallel from the normal direction of the object surface OS irradiate the irradiation area IR of the object surface OS, and are reflected by the irradiation area IR.

The first reflected light RL1 is reflected light obtained by reflecting the incident light IL1 once from the region R of the object surface OS. In the example of FIG. 3, the first reflection direction in which the first reflected light RL1 is reflected from the irradiation area IR is a direction perpendicular to the area R of the object surface OS. It should be noted that the first reflected light RL1 may include reflected light obtained by reflecting once in the region R the incident light whose incident position on the irradiation region IR is different from that of the incident light IL1.

The second reflected lights RL2-1 and RL2-2 (hereinafter collectively referred to as "second reflected lights RL2") are incident lights IL2-1 and IL2-2 that are incident on the irradiation region IR at different positions. , the reflected light reflected at least once by the region R and the convex portion C. FIG.

For example, the second reflected light RL2-1 is obtained by reflecting the incident light IL2-1 at least once on each of the region R and the inclined surface T1 of the convex portion C, that is, at least twice on the irradiation region IR. It is reflected light. The second reflected light RL2-2 is such that the incident light IL2-2, which is incident at a position different from that of the incident light IL2-1, is irradiated at least once on each of the region R and the inclined surface T2 of the convex portion C. It is reflected light reflected at least twice in the region IR.

The reflection direction of the second reflected light RL2-1 reflected by the inclined surface T1 of the convex portion C having the apex angle A and the region R (hereinafter also referred to as the “second reflection direction”) is It is a direction inclined by the same angle as the apex angle A from the normal direction of the region R. The apex angle A may be an angle different from the design apex angle of the riblet structure. That is, the second reflection direction may be a direction inclined from the normal direction of the region R by an angle different from the designed vertical angle.

The reflection direction of the second reflected light RL2-2 reflected by the inclined surface T2 of the convex portion C having the apex angle A and the region R (hereinafter also referred to as the “third reflection direction”) is the direction of the object surface OS. It is a direction inclined by the same angle as the apex angle A in the direction opposite to the second reflection direction with respect to the normal direction of the region R. The apex angle A is an angle different from the designed apex angle of the riblet structure. That is, the third reflection direction may be a direction that is inclined with respect to the normal direction of the region R by an angle different from the designed vertical angle in the direction opposite to the second reflection direction.

The second reflected light beams RL2-1 and RL2-2 are reflected by the region R and the convex portion C three times or more in total, such as once by the region R and twice by the convex portion C. It may be light. In addition to the second reflected lights RL2-1 and RL2-2, the second reflected light RL2 includes incident lights having different incident positions on the irradiation area IR from the incident lights IL2-1 and IL2-2. It may include reflected light that has been reflected at least twice with IR.

The convex portion C may have a height H (eg, 50 μm), and the pair of inclined surfaces T1 and T2 may form an apex angle A (eg, 45°).

FIG. 4 is a schematic diagram showing the configuration of the optical device 1. FIG. The optical device 1 includes a condensing optical system 2 and a light receiving element 3 housed in a housing 4 and is electrically connected to a computer 5 . The connection between the optical device 1 and the computer 5 may be wired or wireless. The optical device 1 irradiates an object surface OS with light from a light source LS and detects reflected light from the object surface OS. FIG. 4 shows cut surfaces of the condensing optical system 2 , the light receiving element 3 , the housing 4 , and the object surface OS by a plane including the optical axis AX of the condensing optical system 2 . Note that the optical device 1 may include the computer 5 .

A light source LS supplies light to the optical device 1 . The light source LS includes, as a light emitting element, an LED (Light Emitting Diode) that emits non-coherent light and/or a laser diode that emits coherent light. Light emitted by the light source LS is guided to the condensing optical system 2 via a light transmitting optical system including, for example, an optical fiber. For example, by using an LED with a short coherent length as the light source LS, interference (speckle) of return light from the surface of the optical member (for example, the surface of the lens member) constituting the light collecting optical system 2 is suppressed. The light source LS may be an SLD (Super Luminescent Diode). Also, the light source LS may be mounted on the optical device 1 .

The condensing optical system 2 irradiates the irradiation area IR of the object surface OS with light from the light source LS, and collects the reflected light reflected by the irradiation area IR.

It should be noted that the light that the condensing optical system 2 irradiates the irradiation region IR may be polarized light. For example, the light source LS may use a polarizer to provide light that is linearly polarized in a predetermined direction. Further, the optical device 1 may further include a polarizing plate that transmits only a polarized component in a predetermined direction out of the light supplied from the light source LS, for example.

The condensing optical system 2 has a lens group 21 having one or more lens members, and a light splitting member 22 arranged closer to the light receiving element 3 than the lens group 21 is. A filter FL for protecting the light receiving element 3 is arranged between the light dividing member 22 and the light receiving element 3 .

The lens group 21 includes, in order from the object surface OS, a positive meniscus lens L1 having a convex surface facing the light receiving element 3 and having positive power, a biconvex positive lens L2 having positive power, and a light receiving lens. It has a positive meniscus lens L3 with a concave surface facing the element 3 side and having positive power.

The positive meniscus lens L1 is a lens member arranged closest to the object surface OS. The positive meniscus lens L1 has a convex surface facing the light receiving element 3 and a concave surface facing the object surface OS.

The positive meniscus lens L3 is a lens member arranged closest to the light splitting member 22 side. The positive meniscus lens L3 has a concave surface facing the light splitting member 22 . Since the lens member arranged closest to the light splitting member 22 has a concave surface facing the light splitting member 22 , it becomes easy to secure a space for arranging the light splitting member 22 .

Table 1 below lists the values of the specifications of the condensing optical system 2 of this embodiment.

In Table 1, m is the order of the optical surfaces counted from the object surface OS side, r is the radius of curvature, d is the interplanar spacing, and ne is the refractive index for the e-line (wavelength 546 nm). A radius of curvature r=∞ indicates a plane.

The unit of length of the radius of curvature r and surface spacing d described in Table 1 is "mm". However, the condensing optical system 2 is not limited to those shown in this table.

(Table 1)
m r d ne
0) ∞ 1.60 (object surface OS)
1) 11.70 12.90 1.839322 (positive meniscus lens L1)
2) -19.47 0.20
3) 60.85 8.50 1.791918 (positive lens L2)
4) -60.85 0.20
5) 26.00 7.00 1.839322 (positive meniscus lens L3)
6) 66.10 3.00
7) ∞ 10.00 1.518251 (light splitting member 22)
8) ∞ 7.50
9) ∞ 0.70 1.518251 (filter FL)
10) ∞ 0.75

As described above, for example, the reflection direction of the second reflected light is a direction inclined by the apex angle A with respect to the normal direction of the region R. In order to set the lower limit of the apex angle A of the convex portion C, which is one of the inspection targets of the object surface OS (riblet structure), to 45°, the numerical aperture of the condensing optical system 2 on the object surface OS side is set to the region R It may be equal to or greater than sin 45° (0.7) so as to properly collect light rays inclined at 45° with respect to the normal direction. Further, in order to set the upper limit of the apex angle A of the convex portion C, which is one of the inspection targets of the object surface OS (riblet structure), to 50°, the numerical aperture of the condensing optical system 2 on the object surface OS side is In order to properly converge the light rays inclined by 50° with respect to the normal direction of the region R, the angle may be equal to sin50° (0.8) or less.

In this case, the numerical aperture of the condensing optical system 2 on the object surface OS side may be determined based on a predetermined margin. For example, the upper limit of the numerical aperture on the object surface OS side of the condensing optical system 2 may be 0.9. The numerical aperture of the condensing optical system 2 on the object surface OS side may be determined according to the upper and lower limits of the apex angle A of the convex portion C to be inspected. That is, the numerical aperture of the condensing optical system 2 on the object surface OS side may be determined based on the apex angle A of the convex portion C (riblet structure) to be inspected.

The lower limit of the apex angle A of the convex portion C to be inspected may be 40° or 30°. When the lower limit of the apex angle A of the convex portion C to be inspected is 40°, the numerical aperture on the object surface OS side of the condensing optical system 2 may be equivalent to sin 40° (0.6) or more. . When the lower limit of the apex angle A of the convex portion C to be inspected is set to 30°, the numerical aperture of the condensing optical system 2 on the object surface OS side must be equivalent to sin30° (0.5) or more. good too.

The upper limit of the apex angle A of the convex portion C to be inspected may be 55° or 65°. When the upper limit of the apex angle A of the convex portion C to be inspected is 55°, the numerical aperture on the object surface OS side of the condensing optical system 2 may be equal to sin 55° (0.8) or less. . Further, when the upper limit of the apex angle A of the convex portion C to be inspected is set to 65°, the numerical aperture on the object surface OS side of the condensing optical system 2 is equivalent to sin 65° (0.9) or less. good too.

The normal line at the end of the effective range of the surface on the object surface OS side of the optical member arranged closest to the object surface OS in the condensing optical system 2 (for example, the surface on the object surface OS side of the lens member); Let β be the angle between the optical system 2 and the optical axis AX. Also, γ is the maximum angle formed by the optical axis AX of the condensing optical system 2 and the light received by the light receiving element 3 among the rays incident on the optical member arranged closest to the object surface OS in the condensing optical system 2 . and γ is the light beam received by the light receiving element 3 among the light beams incident on the optical member arranged closest to the object surface OS in the light collecting optical system 2 and the light beam incident on the object surface OS from the light collecting optical system 2. can be said to be the maximum angle formed by the principal ray of

At this time, by setting γ>β, the light-condensing optical system 2 reflects light from the surface on the object surface OS side of the optical member arranged closest to the object surface OS in the light-condensing optical system 2. , and the reflected light can be appropriately focused on the light receiving element 3 with a simple optical system.

FIG. 5 is a schematic diagram for explaining optical members arranged closest to the object surface OS in the condensing optical system 2 .

The positive meniscus lens L1 included in the lens group 21 of the condensing optical system 2 corresponds to an optical member arranged closest to the object surface OS in the condensing optical system 2 . Let r be the radius of curvature of the lens surface (hereinafter referred to as the first surface) of the positive meniscus lens L1 on the object surface OS side, and φ _eff be the diameter of the effective range of the first surface. With the intersection of the normal at the end of the effective range of the first surface and the optical axis AX of the condensing optical system 2 as the origin (0, 0), the normal at the end of the effective range of the first surface and the condensing optical Let β be the angle between the system 2 and the optical axis AX.

FIG. 5 shows a cut surface of the positive meniscus lens L1 by a plane including the optical axis AX of the condensing optical system 2. FIG. Since the first surface is spherical, a point (x,y) on the first surface satisfies the following equation.

The coordinates of the point P _eff at the upper end of the effective range of the first surface can be expressed as follows.

Let d be the distance on the optical axis of the condensing optical system 2 from the object surface OS to the first surface, and let φ _field be the diameter of the irradiation region IR. The coordinates of the point P _field at the upper end of the irradiation area IR can be expressed as follows.

β corresponds to the slope of a straight line passing through the point P _eff and the origin. γ corresponds to the slope of a straight line passing through the point P _eff and the point P _field . Therefore, for the spherical first surface, the conditional expression γ>β can be expressed as follows.

FIG. 6 is a diagram showing the projection relationship in the condensing optical system 2. FIG.

In the graph GR1, the horizontal axis θ represents the angle formed by the light reflected by the irradiation region IR and the optical axis AX of the condensing optical system 2, and the vertical axis y represents the light converged on the light receiving element 3 by the condensing optical system 2. It represents the radius of the circle circumscribing the range of light. Also, f represents the focal length of the condensing optical system 2 .

The condensing optical system 2 may satisfy the conditional expression y<f sin θ. By satisfying this conditional expression, the range of light converged on the light receiving element 3 does not become too large, and the size of the light receiving element 3 can be reduced. The size of the light receiving element 3 can be said to be the size of the light receiving surface of the light receiving element 3 . As the size of the light receiving surface of the light receiving element 3 becomes smaller, the size of the light receiving element 3 also becomes smaller. Also, the size of the light receiving element 3 can be said to be an area occupied by a plurality of pixels arranged on the light receiving element 3 .

Returning to FIG. 4, the light splitting member 22 reflects at least part of the light emitted from the light source LS via the optical fiber toward the object surface OS. The light from the light source LS reflected by the light splitting member 22 is converted into parallel light along the optical axis AX by the lens group 21, and the irradiation region IR of the object surface OS is irradiated with the parallel light.

The first reflected light RL1 and the second reflected light RL2 reflected by irradiation of parallel light from the condensing optical system 2 (lens group 21) to the irradiation region IR enter the lens group 21 and are guided to the light splitting member 22. be killed.

In the region of the light splitting member 22 through which the first reflected light RL1 is transmitted, part of the first reflected light RL1 is transmitted toward the light receiving element 3, and the other part of the first reflected light RL1 is not incident on the light receiving element 3. For this purpose, an optical thin film TF is provided. For example, the optical thin film TF is provided on the optical path of the first reflected light RL<b>1 in the light splitting member 22 and outside the optical path of the second reflected light RL<b>2 in the light splitting member 22 . For example, the optical thin film TF is provided in a region of the light splitting member 22 that includes the optical axis AX in a plane intersecting the optical axis AX.

The optical thin film TF of the light splitting member 22 reflects the other part of the first reflected light RL1 in a direction different from that of the light receiving element 3. For example, the optical thin film TF is arranged in a direction inclined by 45° with respect to the optical axis AX of the condensing optical system 2, and the other part of the first reflected light RL1 is incident on the optical thin film TF from the light source LS. Reflect in the opposite direction. That is, the first reflected light RL<b>1 does not enter the light receiving element 3 . It can also be said that the optical thin film TF reflects the other portion of the first reflected light RL1 toward the exit end of the optical fiber from which the light from the light source LS is emitted.

The optical thin film TF transmits part of the first reflected light RL1. Part of the first reflected light RL<b>1 that has passed through the optical thin film TF enters the light receiving element 3 . The light amount of the first reflected light RL1 incident on the light receiving element 3 with the optical thin film TF can be made lower than the light amount of the first reflected light RL1 incident on the light receiving element 3 without the optical thin film TF. Also, the second reflected light RL2 enters the light receiving element 3 via the light splitting member 22 without entering the optical thin film TF. Therefore, the light splitting member 22 (optical thin film TF) described above can reduce the light amount difference between the first reflected light RL1 and the second reflected light RL2 incident on the light receiving element 3 .

As described above, the first reflected light RL1 is reflected once by the irradiation region IR, whereas the second reflected light RL2 is reflected by the irradiation region IR multiple times (for example, twice). light, and the light amount of the first reflected light RL1 is greater than the light amount of the second reflected light RL2. If the light amount difference between the first reflected light RL1 and the second reflected light RL2 exceeds the dynamic range of the light receiving element 3, at least one of the first reflected light RL1 and the second reflected light RL2 may not be detected.

Therefore, by reducing the difference between the light amount of the first reflected light RL1 and the light amount of the second reflected light RL2 incident on the light receiving element 3 using the light splitting member 22 (optical thin film TF), the first reflected light RL1 and the second reflected light RL2 can be reliably detected.

For example, the optical thin film TF may be a half mirror, or may be a reflecting film having a reflectance different from 50% for the first reflected light RL1. The optical thin film TF may be a film that reflects or transmits light according to the polarization state of incident light. For example, it may be a film that reflects the s-polarized component of the incident light and transmits the p-polarized component.

Further, the optical thin film TF of the light splitting member 22 may be configured to transmit part of the first reflected light RL1 toward the light receiving element 3 and absorb the other part of the first reflected light RL1.

Note that the optical thin film TF does not have to be provided in the entire optical path of the first reflected light RL1 in the light splitting member 22. For example, the optical thin film TF forms at least one optical path of the first reflected light RL1 in the light splitting member 22 so that at least part of the light flux of the first reflected light RL1 that has entered the light splitting member 22 is incident on the optical thin film TF. may be provided in the department.

Note that the optical thin film TF does not have to be provided outside the optical path of the second reflected light RL2 in the light splitting member 22. The optical thin film TF is provided in a part of the optical path of the second reflected light RL2 in the light splitting member 22 so that a part of the second reflected light RL2 incident on the light splitting member 22 is incident on the optical thin film TF. may be

The light splitting member 22 may be configured such that the amount of light in the part of the first reflected light RL1 is smaller than the amount of light in the other part. For example, the optical thin film TF of the light splitting member 22 may be set to transmit 10% of the incident first reflected light RL1 and reflect 90%. Further, the light splitting member 22 may be set so that the incident light is not substantially reflected, scattered, or absorbed in the region where the second reflected light RL2 is mainly incident.

In addition, the light splitting member 22 transmits part of the first reflected light RL1 toward the light receiving element 3 in a region through which the first reflected light RL1 is transmitted. The optical thin film TF for preventing light from entering the light receiving element 3 may not be provided. For example, the light splitting member 22 is configured such that the transmittance of the first reflected light RL1 of the light splitting member 22 on the optical path is lower than the transmittance of the second reflected light RL2 of the light splitting member 22 on the optical path. may have been For example, the light splitting member 22 is made of a glass material whose transmittance of the first reflected light RL1 is lower than that of the second reflected light RL2. At least part of the region along the optical axis AX of the member 22 is configured, and the second reflected light RL2 in the light splitting member 22 is made of a glass material having a transmittance of the second reflected light RL2 equal to or higher than the transmittance of the first reflected light RL1. may comprise at least a portion of the optical path of

Referring to FIG. 4 again, the light receiving element 3 is, for example, a CMOS or the like having pixels arranged two-dimensionally. The light-receiving element 3 is arranged on the surface where the light is collected so that the areas corresponding to the first reflected light RL1 and the second reflected light RL2 can be identified as different areas in space.

The light-receiving element 3 receives light from the condensing optical system 2 that is irradiated onto the irradiation region IR, is reflected by the irradiation region IR, and is condensed by the condensing optical system 2 (for example, the first reflected light RL1 and at least one of the second reflected light) is output. The data representing the result of light reception is, for example, data representing the intensity distribution of the light condensed by the condensing optical system 2 (for example, at least one of the first reflected light RL1 and the second reflected light). Note that the data representing the intensity distribution may be two-dimensional image data.

That is, the light receiving element 3 can detect the intensity distribution of the light condensed by the condensing optical system 2 . The data representing the intensity distribution output from the light receiving element 3 can also be said to be data based on reflected light from the riblet structure to be inspected. The light receiving element 3 may be an element such as a line sensor having pixels arranged one-dimensionally. Even in this case, data representing the intensity distribution of the light condensed by the condensing optical system 2 can be output.

The light receiving element 3 may be arranged on a plane different from the plane conjugated to the object surface OS with respect to the condensing optical system 2 . Further, the light-receiving element 3 has a light-receiving surface 3a for receiving the light condensed by the condensing optical system 2, and the light-receiving surface 3a is located on a different plane from the surface conjugated to the object surface OS with respect to the condensing optical system 2. may be placed.

The surface conjugate with the object surface OS with respect to the condensing optical system 2 is the image plane of the condensing optical system 2 when the object surface OS is the object plane, or the image surface with respect to another optical system such as a relay optical system. equivalent to the Light entering the condensing optical system 2 from one point on the object surface OS is condensed to one point on the image plane of the condensing optical system 2 . In other words, the first reflected light RL1 and the second reflected light RL2 overlap on the image plane of the condensing optical system 2 or on a plane conjugate with the image plane. Therefore, when the light-receiving element 3 (the light-receiving surface 3a of the light-receiving element 3) is arranged on the image plane of the light collecting optical system 2 or on a plane conjugate with the image plane, the image plane of the light collecting optical system 2 or the plane conjugate with the image plane Since the first reflected light RL1 and the second reflected light RL2 are not separated in this case, they cannot be properly identified on the intensity distribution of the light detected by one light receiving element 3 .

The light-receiving element 3 (light-receiving surface 3a) is arranged on a surface different from the surface conjugated to the object surface OS with respect to the condensing optical system 2, so that one light-receiving element 3 receives the first reflected light RL1 and the second reflected light RL1. The light RL2 can be distinguished and detected. Therefore, the optical device 1 includes a plurality of light receiving elements (for example, three light receiving elements) for individually detecting the first reflected light RL1, the second reflected light RL2-1, and the second reflected light RL2-2. Also, since an optical system for causing reflected light to enter each of the plurality of light receiving elements is not required, the riblet structure can be inspected with a small and inexpensive configuration (simple configuration).

Further, the light receiving surface 3 a may be arranged closer to the exit pupil plane of the light collecting optical system 2 than the optical member arranged closest to the light receiving element 3 among the optical members constituting the light collecting optical system 2 . At this time, the exit pupil of the condensing optical system 2 may be on the side opposite to the object surface OS with respect to the condensing optical system 2 . In this embodiment, the optical member arranged closest to the light receiving element 3 among the optical members constituting the condensing optical system 2 is the light splitting member 22 . In this case, the light-receiving surface 3 a may be arranged at a position closer to the exit pupil plane of the condensing optical system 2 than the distance between the light splitting member 22 and the exit pupil plane of the condensing optical system 2 . Note that the position at which the distance from the exit pupil plane of the condensing optical system 2 is shorter than the distance between the light splitting member 22 and the exit pupil plane of the condensing optical system 2 is closer to the exit pupil plane when viewed from the object surface OS side. It may be at a near position or at a position farther than the exit pupil plane.

With the arrangement described above, the light-receiving surface 3a is located at a position different from a plane conjugated to the object surface OS with respect to the light-condensing optical system 2 (a position different from the image plane of the light-condensing optical system 2 or a plane conjugated with the image plane). , the first reflected light RL1 and the second reflected light RL1 are arranged on the exit pupil plane of the condensing optical system 2 or in the vicinity of the exit pupil plane. The light RL2 can be properly discriminated.

Also, the size of the area occupied by the light-receiving surface 3a that is incident on the light-receiving optical system 2 from one point on the object surface OS and reaches the light-receiving element 3 at the maximum numerical aperture on the object surface OS side of the light-receiving optical system 2 is , may be larger than 0 times the size of the light receiving surface 3a. In other words, the luminous flux incident on the light-receiving optical system 2 from one point on the object surface OS at the maximum numerical aperture on the object surface OS side of the light-receiving optical system 2 and reaching the light receiving element 3 is on the light receiving surface 3a of the light receiving element 3. (It is not necessary to create a condensing point on the light receiving surface 3a). In other words, it is not necessary to create an image of the object surface OS on the light receiving surface 3 a of the light receiving element 3 . The size of the region may be, for example, 0.1 times or more the size of the light receiving surface 3a. In this case, the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 can be properly identified on the intensity distribution of light detected by one light receiving element 3. FIG.

It is assumed that the area of one point on the object surface OS is 0. For example, at the maximum numerical aperture on the object surface OS side of the light collecting optical system 2, the size of the area occupied by the light beam entering the light collecting optical system 2 from one point on the object surface OS and reaching the light receiving element 3 on the light receiving surface 3a is , the size of the light receiving surface 3a is 0 times the size of the light receiving surface 3a. It will be placed. When the size of the area is 0 times the size of the light receiving surface 3a, that is, when the light is focused on one point on the light receiving surface 3a, the first reflected light RL1 and the second reflected light RL2 overlap on the light receiving surface 3a. , the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 cannot be properly identified on the intensity distribution of light detected by one light receiving element 3 .

The size of the area may not be 0.1 times or more the size of the light receiving surface 3a, and may be, for example, 0.001 times or more, 0.01 times or more, 1 time or more, and 10 times or more. It can be either.

The light-receiving surface 3a may be arranged on a surface that has an optical Fourier transform relationship with the object surface OS by the condensing optical system 2 . Note that the surface that is optically Fourier transformed with respect to the object surface OS by the condensing optical system 2 may be referred to as the pupil plane of the condensing optical system 2 . Alternatively, it may be arranged in a pupil space defined by the pupil plane of the condensing optical system 2 and the entrance-side optical surface adjacent to the pupil plane.

In the condensing optical system 2, the diameter of the light flux supplied from the light source LS to the light splitting member 22 corresponds to the diameter of the aperture stop. For example, the exit pupil plane of the condensing optical system 2 is a position where the diameter of the light beam emitted from the light source LS is restricted (for example, the end face of the optical fiber connecting the light source LS and the light splitting member 22 on the light splitting member 22 side). It is a conjugate aspect with

In the optical device 1 of the present embodiment, the light receiving surface 3a is arranged on the exit pupil plane of the condensing optical system 2, as an example. The light-receiving surface 3a may be arranged on a plane that is conjugate with the exit pupil plane of the condensing optical system 2 with respect to the other optical system, such as a relay optical system.

The optical device 1 may include a plurality of light receiving elements for individually detecting the first reflected light RL1, the second reflected light RL2-1, and the second reflected light RL2-2, An optical system may be provided for making reflected light incident on each of the plurality of light receiving elements.

The light source LS may have an aperture stop on the surface from which the light beam is emitted, or on a surface conjugate with the surface from which the light beam emitted from the light source LS is emitted with respect to the light transmitting optical system on which the light emitted from the light source LS is incident. With such an aperture stop, it is possible to appropriately set the divergence angle of the light beam directed to the irradiation area IR irradiated with light by the light condensing optical system 2 . In addition, it can be said that the numerical aperture of the condensing optical system 2 on the object surface OS side (irradiation area IR side) can be appropriately adjusted by the aperture stop.

It should be noted that the light-sending optical system may include a relay optical system. Note that the light-transmitting optical system may include a field stop. For example, when the light-sending optical system has a relay optical system, the relay optical system may have a field stop. With the field stop, it is possible to appropriately set the range of the irradiation region IR onto which the light is irradiated by the condensing optical system 2 .

A light intensity measuring device for measuring the intensity of light emitted from the light source LS may be provided. The light intensity measuring device may be arranged on an optical path divided by a beam splitter such as a half mirror arranged on the optical path of light emitted from the light source LS and applied to the irradiation region IR. A light intensity measuring device may measure the intensity of the light split by this beam splitter. Note that the output of the light source LS may be adjusted based on the intensity of the light emitted from the light source LS measured by the light intensity measuring device.

FIG. 7 is a schematic diagram showing the first received light data (an example of an image indicated by the first received light data).

In the first light reception data RD1, which is an example of light reception data representing the result of light reception, the amount of light corresponding to the first reflected light RL1 is represented in the central region around the optical axis AX of the light collecting optical system 2, and the second reflected light RL2 The amount of light corresponding to is represented in areas other than the central area. For explanation, FIG. 7 shows a virtual line HL1 corresponding to a direction perpendicular to the first direction D1 in which the convex portions C are arranged on the object surface OS.

When the inclined surface T1 and the inclined surface T2 of the convex portion C are symmetrical with respect to the third direction D3, the pair of second reflected light beams RL2-1 and RL2-2 included in the second reflected light beam RL2 are aligned along the virtual line HL. , are symmetrical with respect to the position corresponding to the optical axis AX of the condensing optical system 2 . In the first received light data RD1, the first reflected light RL1 is represented at a position along the imaginary line HL1.

The light reception data representing the result of light reception may be data representing the intensity distribution of the light condensed on the light receiving surface 3a by the condensing optical system 2. The data representing the intensity distribution of the light condensed on the light receiving surface 3a by the condensing optical system 2 is not limited to a two-dimensional image such as the first received light data RD1 shown in FIG. The data may be data representing the intensity distribution of the amount of light. Further, either one of the second reflected light RL2-1 and RL2-2 of the second reflected light RL2 may not be represented in the light reception data representing the result of light reception. For example, the light receiving element 3 detects at least one of the second reflected light RL2-1 and the second reflected light RL2-2 of the second reflected light RL2 condensed on the light receiving surface 3a by the condensing optical system 2. may

Referring to FIG. 4 again, the housing 4 is a housing that accommodates the condensing optical system 2 and the light receiving element 3, and is made of a plastic material such as polypropylene or ABS resin. The housing 4 may be made of a metal material such as an aluminum alloy.

The housing 4 has a contact member 4a. The contact member 4a protrudes closer to the object surface OS than the positive meniscus lens L1, which is arranged closest to the object surface OS among the optical members constituting the condensing optical system 2, and can come into contact with the object surface OS. The contact member 4a can contact at least a partial area of the object surface OS excluding the irradiation area IR.

The contact member 4a and the condensing optical system 2 are arranged in the direction of the optical axis AX of the condensing optical system 2 between the condensing optical system 2 and the object surface OS when the contact member 4a contacts the object surface OS. is the working distance WD of the condensing optical system 2 on the object surface OS side. In the optical device 1 in which the contact member 4a and the optical condensing system 2 are arranged in this manner, the distance between the optical condensing system 2 and the object surface OS is reduced by bringing the contact member 4a into contact with the object surface OS. is the working distance WD of the condensing optical system 2 on the object surface OS side, the object surface OS can be easily inspected.

The contact member 4a has a support member 4b. For example, the support member 4b may support the positive meniscus lens L1 of the condensing optical system 2. FIG. The support member 4b may support the positive meniscus lens L1 so that the position of the positive meniscus lens L1 with respect to the housing 4 does not change. The support member 4b is such that when the contact member 4a abuts on the object surface OS, the distance between the light collecting optical system 2 and the object surface OS in the direction of the optical axis AX of the light collecting optical system 2 is equal to that of the light collecting optical system 2. The positive meniscus lens L1 arranged closest to the object surface OS may be supported so that the working distance WD on the object surface OS side is . In addition to the positive meniscus lens L1, the support member 4b also includes other optical members of the condensing optical system 2 (at least one of the positive lens L2, the positive meniscus lens L3, and the light splitting member 22) and the light receiving element 3. You may support at least one.

The contact member 4a may be made of a material having a lower hardness than the material forming the convex portions C of the object surface OS in order to prevent deformation of the object surface OS due to contact with the object surface OS.

The contact member 4 a may be formed integrally with the housing 4 . Further, the contact member 4a does not have to directly support the optical members and the light receiving element 3 included in the condensing optical system 2, and other members may support them.

Note that the optical device 1 does not have to be brought into contact with the object surface OS. Further, the housing 4 may not have the contact member 4a.

The computer 5 is an information processing device that acquires light reception data from the light receiving element 3 and inspects the object surface OS.

The computer 5 is communicably connected to the optical device 1 according to existing communication standards such as USB (Universal Serial Bus, registered trademark) or Bluetooth (registered trademark).

FIG. 7 is a schematic diagram showing a schematic configuration of the computer 5. FIG.

The computer 5 has an input/output interface 51, a memory 52, and a processor 53.

The input/output interface 51 is an example of a communication section, and has an interface circuit for receiving data to be processed by the computer 5 or for outputting data processed by the computer 5 . The input/output interface 51 includes, for example, a peripheral device interface circuit for connecting the computer 5 to various peripheral devices such as the optical device 1, a keyboard, and a display, or a communication interface circuit for connecting the computer 5 to a communication network.

The memory 52 is an example of a storage unit, and has a volatile semiconductor memory and a nonvolatile semiconductor memory. The memory 52 stores various data used for processing by the processor 53, such as light receiving data obtained from the light receiving element 3, reference data for inspecting the riblet structure, threshold values, and the like. The memory 52 also stores various application programs such as an inspection program for executing inspection processing. The reference data for inspecting the riblet structure can also be said to be reference data for inspecting the riblet structure.

The processor 53 is an example of a control unit and has one or more processors and their peripheral circuits. Processor 53 may further comprise other arithmetic circuitry such as a logic arithmetic unit, a math unit, or a graphics processing unit.

FIG. 9 is a functional block diagram of the processor 53 that the computer 5 has.

The processor 53 of the computer 5 has a calculation unit 531, a detection unit 532, and a measurement unit 533 as functional blocks. Each of these units of processor 53 is a functional module implemented by a program executed on processor 53 . A computer program that implements the function of each unit of the processor 53 may be provided in a form recorded in a computer-readable portable recording medium such as a semiconductor memory, magnetic recording medium, or optical recording medium. Alternatively, each of these units of processor 53 may be implemented in computer 5 as separate integrated circuits, microprocessors, or firmware.

The computation unit 531 executes computation including inspection of the riblet structure on the object surface OS based on the received light data RD acquired from the light receiving element 3 . The object surface OS is an example of an inspected surface to be inspected in the computation by the computing unit 531 . The received light data RD acquired from the light receiving element 3 may be, as described above, data representing the intensity distribution of light condensed on the light receiving surface 3a by the condensing optical system 2, such as image data. Note that the calculation unit 531 can also be called an inspection unit because it inspects the riblet structure.

The computing unit 531 inspects at least one of the convex portion C, the region R, the convex portion C, and the region R in the inspection of the object surface OS.

The calculation unit 531 may determine the quality of the shape of the convex portion C as an inspection of the riblet structure based on the data representing the intensity distribution.

The calculation unit 531 may inspect the riblet structure based on the comparison result between the intensity of the first reflected light RL1 incident on the light receiving surface 3a and the intensity of the second reflected light RL2 incident on the light receiving surface 3a. For example, the calculation unit 531 determines the riblet structure as an inspection of the riblet structure based on the comparison result between the intensity of the first reflected light RL1 incident on the light receiving surface 3a and the intensity of the second reflected light RL2 incident on the light receiving surface 3a. You may judge the quality of the shape of. For example, the calculation unit 531 may determine the quality of the shape of the convex portion C as the quality of the shape of the riblet structure.

The intensity of the reflected light incident on the light receiving surface 3a corresponds to the brightness of the area corresponding to the reflected light in the data representing the intensity distribution detected by the light receiving element 3 (on the image represented by the intensity distribution data). The calculation unit 531 identifies the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 (on the image represented by the intensity distribution data) from the data representing the intensity distribution. For example, the computing unit 531 extracts pixels whose brightness values are equal to or greater than a predetermined threshold value on the image represented by the intensity distribution data, and clusters and groups the extracted pixels so that the intensity distribution data represents A region corresponding to the first reflected light RL1 and a region corresponding to the second reflected light RL2 are specified on the image.

The calculation unit 531 calculates statistical representative values such as the maximum value (peak), average value, mode value, and median value of the brightness of each specified region. Note that the representative value of the brightness of the area corresponding to the first reflected light RL1 calculated by the calculation unit 531 represents the intensity of the first reflected light RL1 incident on the light receiving surface 3a. Also, the representative value of the luminance of the area corresponding to the second reflected light RL2 calculated by the calculation unit 531 represents the intensity of the second reflected light RL2 incident on the light receiving surface 3a. Then, the calculation unit 531 calculates the representative value of the brightness of the area corresponding to the first reflected light RL1 and the representative value of the brightness of the area corresponding to the second reflected light RL2 in the data representing the intensity distribution (on the image represented by the intensity distribution data). By comparing the values, the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2 are compared.

Note that the calculation unit 531 may calculate at least one of the statistical representative values described above. That is, the calculation unit 531 may calculate at least one of the maximum value (peak), average value, mode value, and median value of the brightness of each specified region. It should be noted that the calculation unit 531 is not limited to clustering, and uses other methods to obtain the area corresponding to the first reflected light RL1 (on the image represented by the intensity distribution data) and the second reflected light RL2 from the data representing the intensity distribution. may be identified.

For example, the calculation unit 531 may use template matching to specify the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 on the image represented by the intensity distribution data. In this case, the calculation unit 531 uses the reference data representing the intensity distribution as the reference of the first reflected light RL1 and the second reflected light RL2 as a template, and combines the template with the data representing the intensity distribution output from the light receiving element 3. By comparing , the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 on the image represented by the intensity distribution data may be identified.

In comparing the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2, the computing unit 531 obtains the ratio between the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2. Further, in comparing the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2, the calculation unit 531 may obtain the difference between the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2. .

For example, on the object surface OS where the tops of the convex portions C are missing (worn) and rounded due to friction with the fluid, etc., the reduction in fluid resistance due to the riblet structure may not be sufficient. Since the intensity of the second reflected light reflected in the reflection direction of the above-described second reflected light RL2 (that is, the second reflection direction and the third reflection direction) is reduced, the object surface where the top of the convex portion C is missing The intensity of the second reflected light RL2 reflected at OS is reduced compared to the intensity of the second reflected light RL2 reflected at the non-truncated object surface OS. Therefore, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2 reflected by the object surface OS where the top of the convex portion C is missing is The brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2 reflected by the object surface OS that is not exposed to the surface OS changes (eg, decreases) from the statistically representative value.

More specifically, the object surface OS with the apex of the convex portion C missing is compared with the object surface OS without the apex of the convex portion C with a predetermined apex angle A (for example, 45° ) is reduced (inclined surface T1 and inclined surface T2). Therefore, the light amount of the second reflected light RL2 decreases due to the decrease in the amount of the light incident on the object surface OS that is reflected by the inclined surface of the convex portion C.

It should be noted that the second reflected light RL2 reflected by the object surface OS where the apex of the convex portion C is missing is compared with the second reflected light RL2 reflected by the object surface OS where the apex is not missing. It can be said that the light is dispersed over a wider area of the light receiving surface 3a. Therefore, the statistical representative value of the brightness of the area corresponding to the second reflected light RL2 reflected by the object surface OS with the missing top is the second reflected light reflected by the object surface OS without the missing top. It can also be said that it changes from the statistical representative value of the brightness of the area corresponding to RL2.

In addition, even if the top of the convex portion C is missing, if the state of the region R does not change, the light reflected in the region R is greater than when the top of the convex portion C is not missing. The statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the first reflected light RL1 does not substantially change.

As described above, the ratio between the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2 reflected by the object surface OS where the top of the convex portion C is missing is the intensity of the first reflected light RL1 and the convex The top of the shaped portion C changes from the ratio of the intensity of the second reflected light RL2 reflected by the object surface OS that is not missing.

The calculation unit 531 calculates, for example, the value of the ratio of the intensity of the second reflected light RL2 to the intensity of the first reflected light RL1 calculated based on the received light data RD (that is, the intensity distribution data corresponding to the first reflected light RL1). The difference between the ratio of the representative value of the luminance of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2 to the representative value of the luminance of the area on the image represented by ) and the reference ratio value exceeds a predetermined threshold value, it may be determined that the rounding of the vertices of the convex portion C as the shape of the convex portion C on the object surface OS is defective.

It should be noted that the poor rounding of the apex of the convex portion C may be a state in which the apex of the convex portion C is relatively largely missing (worn) due to friction with fluid or the like. In addition, it can be said that the roundness of the vertex of the convex portion C is poor because the convex portion C is deteriorated. The roundness of the apex of the convex portion C as the shape of the convex portion C can be said to be the curvature of the apex of the convex portion C, or the curvature radius of the apex of the convex portion C.

It should be noted that the above reference ratio value can also be said to be reference data for inspecting the quality of the riblet structure (the convex portion of the object surface OS). When the convex portion C has a shape that can be regarded as a non-defective product (for example, the top of the convex portion C is not missing), the ratio value of this reference is actually the convex portion C and the region R of the non-defective product. may be the ratio of the intensity of the second reflected light RL2 to the intensity of the first reflected light RL1 reflected by irradiating light onto the object surface OS on which is formed. The value of this reference ratio is calculated by a simulation using a ray tracing method, etc., when it is assumed that the surface on which the convex portion C and the region R of the non-defective product are formed is irradiated with light. It may be a ratio of the intensity of the second reflected light RL2 to the intensity of the reflected light RL1.

Note that if the calculated ratio of the intensity of the second reflected light RL2 to the intensity of the first reflected light RL1 is different from the reference ratio, the calculation unit 531 may may be determined to be defective. For example, when the calculated ratio of the intensity of the second reflected light RL2 to the intensity of the first reflected light RL1 is lower than the reference ratio, the calculation unit 531 determines that the apex of the convex portion C is rounded. It may be judged as defective.

FIG. 10 is a diagram explaining the luminance ratio between the first reflected light RL1 and the second reflected light RL2 in the first received light data RD1.

For example, in the graph GR2 corresponding to the first received light data RD1, the horizontal axis indicates the position on the virtual line HL1, and the vertical axis indicates the luminance ratio when the peak luminance corresponding to the first reflected light RL1 is set to 1. show. The peak corresponding to the first reflected light RL1 appears between the peak corresponding to the second reflected light RL2-1 and the peak corresponding to RL2-2 on the virtual line HL1. The luminance ratio value at the peak corresponding to the pair of second reflected lights RL2-1 and RL2-2 appearing on the virtual line HL1 is 0.3.

For example, when the reference data (for example, the value of the above reference ratio) for inspecting the quality of the riblet structure (the convex portion of the object surface OS) is 0.2, and the predetermined threshold is ±0.2. , the difference between the luminance ratio 0.3 at the peaks corresponding to the second reflected lights RL2-1 and RL2-2 and the reference ratio value 0.2 is 0.1, exceeding the predetermined threshold ±0.2. Therefore, the calculation unit 531 determines that the roundness of the vertices of the convex portion C as the shape of the convex portion C of the object surface OS is good.

It should be noted that the target of quality determination by the computing unit 531 is not limited to the roundness of the apex of the convex portion C. For example, the calculation unit 531 performs the above-described processing to determine the apex angle A of the convex portion C, the height H of the convex portion C, and the height of the convex portion C as the shape of the riblet structure (the shape of the convex portion C). At least one of the symmetry and the interval P between the convex portions C in the second direction D2 may be determined.

Note that the calculation unit 531 may also use the intensity of the light emitted from the light source LS, which is output from the light intensity measuring device described above, to determine the quality of the riblet structure.

Note that the calculation unit 531 does not have to use the second reflected light RL2-1 or the second reflected light RL2-2 of the second reflected light RL2 for the quality inspection of the riblet structure described above. In this case, the computing unit 531 calculates the intensity of the second reflected light RL2-1 (that is, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2-1), or It is not necessary to calculate the intensity of the second reflected light RL2-2 (that is, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2-2).

For example, the computing unit 531 calculates the ratio between the intensity of the first reflected light RL1 and the intensity of the second reflected light RL2-1 (that is, the luminance of the area on the image represented by the intensity distribution data corresponding to the first reflected light RL1). ratio of the representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2-1, or the intensity of the first reflected light RL1 and the second reflection The ratio of the intensity of the light RL2-2 (that is, the statistical representative value of the luminance of the area on the image represented by the intensity distribution data, corresponding to the first reflected light RL1, corresponding to the second reflected light RL2-2, The quality of the shape of the riblet structure is determined by calculating the ratio of the statistical representative values of the brightness of the area on the image represented by the intensity distribution data) and comparing it with the reference data for checking the quality of the riblet structure. (For example, whether or not the vertex of the convex portion C is rounded) may be determined.

It should be noted that the calculation unit 531 does not have to use the first reflected light RL1 for inspecting the quality of the riblet structure described above. In this case, the computing unit 531 does not need to calculate the intensity of the first reflected light RL1 (that is, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the first reflected light RL1). good. For example, the calculation unit 531 calculates the intensity of the second reflected light RL2 (that is, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2), and calculates the intensity of the riblet structure. The quality of the shape of the riblet structure (for example, the quality of rounding of the apex of the convex portion C) may be determined by comparing with reference data for quality inspection.

In this case, the reference data for inspecting the quality of the riblet structure is the object surface on which the convex portion C and the region R of the non-defective product are actually formed when the convex portion C has a shape that can be regarded as a non-defective product. It may be the reference intensity of the second reflected light RL2 reflected by irradiating the OS with light, or may be the reference intensity of the second reflected light RL2 calculated by simulation.

The calculation unit 531 calculates the intensity of the second reflected light RL2-1 in the second reflected light RL2 (that is, the statistics of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2-1). typical representative value), or the intensity of the second reflected light RL2-2 (that is, the statistical representative value of the brightness of the area on the image represented by the intensity distribution data corresponding to the second reflected light RL2-2), The quality of the shape of the riblet structure may be determined by comparing with the reference data for testing the quality of the riblet structure.

For example, the computing unit 531 compares the difference between the calculated intensity of the second reflected light RL2-1 and the reference intensity of the second reflected light RL2-1 with a predetermined threshold to judge the quality of the shape of the riblet structure. You can judge. The calculation unit 531 compares the difference between the calculated intensity of the second reflected light RL2-2 and the reference intensity of the second reflected light RL2-2 with a predetermined threshold to determine the quality of the shape of the riblet structure. may

Note that, for example, the calculation unit 531 may determine that the shape of the riblet structure is defective when the calculated intensity of the second reflected light RL2-1 is different from the reference intensity of the second reflected light RL2-1. The calculation unit 531 may determine that the shape of the riblet structure is defective when the calculated intensity of the second reflected light RL2-2 is different from the reference intensity of the second reflected light RL2-2.

For example, the computing unit 531 determines that the shape of the riblet structure is defective when the calculated intensity of the second reflected light RL2-1 is lower than the reference intensity of the second reflected light RL2-1. may The calculation unit 531 may determine that the shape of the riblet structure is defective when the calculated intensity of the second reflected light RL2-2 is lower than the reference intensity of the second reflected light RL2-2.

The calculation unit 531 calculates the distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1 on the light receiving surface 3a, the incident position of the first reflected light RL1 and the second reflected light RL2- An inspection of the riblet structure may be performed based on the two incident positions and the spacing. For example, the calculation unit 531 calculates the distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1 on the light receiving surface 3a, the incident position of the first reflected light RL1, and the second reflected light. The quality of the shape of the riblet structure as an inspection of the riblet structure may be determined based on the distance from the incident position of RL2-2. For example, the calculation unit 531 may determine the quality of the shape of the convex portion C as the quality of the shape of the riblet structure.

The incident position of the reflected light on the light receiving surface 3a corresponds to the position of the area corresponding to the reflected light in the data representing the intensity distribution detected by the light receiving element 3 (on the image represented by the intensity distribution data). As described above, the calculation unit 531 identifies the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 (on the image represented by the intensity distribution data) from the data representing the intensity distribution. For example, the computing unit 531 extracts pixels whose brightness values are equal to or greater than a predetermined threshold value on the image represented by the intensity distribution data, and clusters and groups the extracted pixels. Note that the calculation unit 531 may use template matching to specify the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 on the image represented by the intensity distribution data.

The computing unit 531 calculates the position of the pixel having the maximum luminance and the region corresponding to the region corresponding to the first reflected light RL1 and the region corresponding to the second reflected light RL2 on the specified image represented by the intensity distribution data. At least one of the positions of the geometrical center of gravity of is calculated as a representative position of the reflected light.

Note that the position corresponding to the first reflected light RL1 (representative position of the first reflected light RL1) on the image represented by the intensity distribution data calculated by the calculation unit 531 is the position of the first reflected light RL1 on the light receiving surface 3a. represents the incident position. Further, the position corresponding to the second reflected light RL2 (representative position of the second reflected light RL2) on the image represented by the intensity distribution data calculated by the calculation unit 531 is the position of the second reflected light RL2 on the light receiving surface 3a. represents the incident position.

Then, the computing unit 531 calculates the position corresponding to the first reflected light RL1 (representative position of the first reflected light RL1) and the second reflected lights RL2-1 and RL2- on the specified image represented by the intensity distribution data. 2 (representative position of the second reflected light RL2), the position corresponding to the first reflected light RL1 and the position corresponding to the second reflected light RL2-1 on the image represented by the intensity distribution. and the distance between the position corresponding to the first reflected light RL1 and the position corresponding to the second reflected light RL2-2.

Note that the interval between the position corresponding to the first reflected light RL1 and the position corresponding to the second reflected light RL2-1 on the image represented by the intensity distribution is the same as the incident position of the first reflected light RL1 and the second reflected light RL2. It represents the distance from the incident position of -1. Further, the interval between the position corresponding to the first reflected light RL1 and the position corresponding to the second reflected light RL2-2 on the image represented by the intensity distribution is the incident position of the first reflected light RL1 and the second reflected light RL2. It represents the distance from the incident position of -2.

For example, the second reflected light RL2-1 is light reflected by the inclined surface T1 and the region R of the convex portion C, and the second reflected light RL2-2 is reflected by the inclined surface T2 and the region R of the convex portion C. It is the light that is made. When the inclination of the inclined surface T1 and the inclination of the inclined surface T2 are not symmetrical with respect to the third direction D3, the reflection direction of the second reflected light RL2-1 and the reflection direction of the second reflected light RL2-2 are not symmetrical. . As a result, the distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1, the distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-2, and is different. The calculation unit 531 calculates the calculated interval between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1, the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-2. If the difference between the ratio or difference between the interval and the reference ratio value or the reference difference value exceeds a predetermined threshold value, the symmetry of the convex portion C as the shape of the convex portion C is judged to be bad. can do.

The calculation unit 531 calculates the calculated distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1, the incident position of the first reflected light RL1, and the incident position of the second reflected light RL2-2. If the difference between the ratio or difference between the intervals and the reference ratio value or reference difference value does not exceed a predetermined threshold value, the symmetry of the convex portion C as the shape of the convex portion C is considered to be good. can judge.

It should be noted that the above standard values can also be said to be standard data for inspecting the quality of the riblet structure. This reference value is used when the convex portion C has a shape that can be regarded as a non-defective product (for example, one inclined surface T1 and the other inclined surface T2 of the convex portion C are symmetrical with respect to the third direction D3). In addition, the incident position of the first reflected light RL1 on the light receiving surface 3a and the second reflected light RL2, which are actually reflected by irradiating the object surface OS on which the convex portion C and the region R of the non-defective product are formed, are shown. -1 to the distance between the position of incidence of the first reflected light RL1 on the light receiving surface 3a and the position of incidence of the second reflected light RL2-2 on the light receiving surface 3a, or It can be a difference.

It should be noted that this reference value is calculated by a simulation using a ray tracing method or the like, assuming that the surface on which the convex portion C and the region R of the non-defective product are formed is irradiated with light. The distance between the incident position of the light RL1 on the light receiving surface 3a and the incident position of the second reflected light RL2-1 on the light receiving surface 3a, the incident position of the first reflected light RL1 on the light receiving surface 3a, and the second reflected light RL2- It may be a ratio or a difference between the two incident positions on the light receiving surface 3a.

Note that the calculation unit 531 calculates the distance between the calculated incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1, and the distance between the calculated incident position of the first reflected light RL1 and the second reflected light RL2-2. The symmetry of the convex portion C may be determined to be poor when the ratio value or the difference value between the distance from the incident position is different from the reference ratio value or the reference difference value. . Note that the calculation unit 531 calculates the calculated distance between the incident position of the first reflected light RL1 and the incident position of the second reflected light RL2-1, the incident position of the first reflected light RL1, and the incident position of the second reflected light RL2-2. It may be determined that the symmetry of the convex portion C is bad when the distance from the position is different.

Note that the calculation unit 531 calculates the incident position of the first reflected light RL1 on the light receiving surface 3a, the incident position of the second reflected light RL2-1 on the light receiving surface 3a, and the light receiving surface 3a of the second reflected light RL2-2. The symmetry of the convex portion C as the shape of the convex portion C may be determined based on the incident position of the beam.

In this case, as described above, the computing unit 531 calculates the position corresponding to the first reflected light RL1 (representative position of the first reflected light RL1), the second reflected light RL2-1, and the second reflected light RL2-1 on the image represented by the intensity distribution data. The position corresponding to RL2-2 (the representative position of the second reflected light RL2) is calculated as the incident position of each reflected light.

Then, the calculation unit 531 calculates the difference (interval) between the calculated incident position of the first reflected light RL1 on the light receiving surface 3a and the reference incident position of the first reflected light RL1, and the calculated second reflected light RL2-1. The difference (interval) between the incident position on the light receiving surface 3a and the reference incident position of the second reflected light RL2-1, and the calculated incident position of the second reflected light RL2-2 on the light receiving surface 3a and the second reflection The quality of the shape of the riblet structure (for example, the quality of the symmetry of the convex portion C) may be determined based on the difference (interval) from the reference incident position of the light RL2-2.

For example, the computing unit 531 calculates the difference between the incident position of the first reflected light RL1 and the reference incident position of the first reflected light RL1, the incident position of the second reflected light RL2-1 and the second reflected light. At least one of the difference from the reference incident position of RL2-1 and the difference between the incident position of the second reflected light RL2-2 and the reference incident position of the second reflected light RL2-2 exceeds a predetermined threshold. , the shape of the riblet structure (for example, the symmetry of the convex portion C) may be determined to be defective.

It should be noted that the above reference incident position can also be said to be reference data for inspecting the quality of the riblet structure. The above reference incident position is the case where the riblet structure has a shape that can be regarded as a non-defective product (for example, one inclined surface T1 and the other inclined surface T2 of the convex portion C are symmetrical with respect to the third direction D3). In addition, the reference incident position of the second reflected light RL2-1 on the light-receiving surface 3a and the second reflected light RL2- 2 may be a reference incident position to the light receiving surface 3a.

Note that the above reference incident positions are the reference incident position of the first reflected light RL1 on the light receiving surface 3a, the reference incident position of the second reflected light RL2-1 on the light receiving surface 3a, and the reference incident position on the light receiving surface 3a. and the reference incident position of the second reflected light RL2-2 on the light receiving surface 3a.

Note that the difference between the incident position of the first reflected light RL1 and the reference incident position of the first reflected light RL1, the difference between the incident position of the second reflected light RL2-1 and the reference incident position of the second reflected light RL2-1. By comparing at least one difference between the difference and the difference between the incident position of the second reflected light RL2-2 and the reference incident position of the second reflected light RL2-2 with a predetermined threshold, the intensity distribution data is At least one of the position of the first reflected light RL1, the position of the second reflected light RL2-1, and the position of the second reflected light RL2-2 in the represented image (in other words, intensity distribution) is the first reflected light It can also be said that the riblet structure is inspected by determining whether or not at least one of the position of RL1, the position of the second reflected light RL2-1, and the position of the second reflected light RL2-2 is included in the reference range. .

It should be noted that the object of quality determination by the computing unit 531 is not limited to the symmetry of the convex portion C. For example, the calculation unit 531 performs the above-described processing to determine the roundness of the convex portion C, the apex angle A of the convex portion C, the height of the convex portion C, and the height of the convex portion C as the shape of the riblet structure (the shape of the convex portion C). The quality of at least one of H and the interval P between the convex portions C in the second direction D2 may be determined.

Note that the calculation unit 531 does not use the incident position of the first reflected light RL1 on the light receiving surface 3a, but calculates the incident position of the second reflected light RL2-1 on the light receiving surface 3a The quality of the shape of the riblet structure (for example, the quality of the symmetry of the convex portion C as the shape of the convex portion C of the riblet structure) may be determined based on the incident position on the surface 3a.

In this case, in the same manner as described above, the computing unit 531 calculates positions corresponding to the second reflected lights RL2-1 and RL2-2 (representative positions of the second reflected light RL2) on the image represented by the intensity distribution data. It is calculated as the incident position of the reflected light.

Then, the calculation unit 531 calculates the difference (interval) between the calculated incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-1, and the calculated second reflected light RL2-1. By comparing the difference (interval) between the incident position of the light RL2-2 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-2, the quality of the shape of the riblet structure (for example, the convex portion C) can be determined. symmetry) may be determined.

For example, the computing unit 531 calculates the difference between the calculated incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-1, and the calculated second reflected light RL2- 2 and the reference incident position of the second reflected light RL2-2 exceeds a predetermined threshold value, it may be determined that the shape of the riblet structure is defective. .

It should be noted that the above reference incident position can also be said to be reference data for inspecting the quality of the riblet structure. When the riblet structure has a shape that can be regarded as a non-defective product, the above reference incident position is the second reflected light RL2-1 that is actually reflected by irradiating the object surface OS on which the riblet structure of a non-defective product is formed. The reference incident position on the light receiving surface 3a and the reference incident position on the light receiving surface 3a of the second reflected light RL2-2 may be used.

The reference incident position is the reference incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-2 on the light receiving surface 3a, which are calculated by simulation. may be

Note that the calculation unit 531 calculates the value of the difference between the calculated incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-1, and the calculated second reflected light If the value of the difference between the incident position of RL2-2 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-2 is different, the shape of the riblet structure (for example, the symmetry of the convex portion C ) may be determined to be defective.

Here, for example, the symmetry of the convex portion C can be said to be the symmetry of one inclined surface T1 and the other inclined surface T2 of the pair of inclined surfaces with respect to the third direction D3. For example, as described above, when the calculation unit 531 determines that the symmetry is poor, the inclined surface T1 and the inclined surface T2 are in an asymmetrical (broken symmetry) state with respect to the third direction D3. It can be said.

The symmetry of the convex portion C can also be said to be the relationship between the angle formed by the region R and the inclined surface T1 on one side and the angle formed by the region R by the inclined surface T2 on the other side. If these angles are different, it can be said that the inclined surface T1 and the inclined surface T2 are in an asymmetrical (loose symmetry) state with respect to the third direction D3.

When the region R with which one inclined surface T1 is in contact and the region R with which the other inclined surface T2 is in contact are included in the same plane or two parallel planes, the second reflection is reflected by one inclined surface T1. The direction of the light RL2-1 and the direction of the second reflected light RL2-2 reflected by the other inclined surface T2 represent the inclination of the plane in which the region R is included with respect to the normal direction. The distance between the position corresponding to the first reflected light RL1 and the positions corresponding to the second reflected lights RL2-1 and RL2-2 correspond to the directions of the second reflected lights RL2-1 and RL2-2, respectively.

Based on the distance between the position corresponding to the first reflected light RL1 and the positions corresponding to the second reflected lights RL2-1 and RL2-2, the calculation unit 531 calculates one of the pair of tilted surfaces and the other tilted surface. may be determined for symmetry with the inclined plane of . For example, the computing unit 531 calculates the distance between the position corresponding to the first reflected light RL1 and the position corresponding to the second reflected light RL2-1, the position corresponding to the first reflected light RL1 and the second reflected light RL2-2. If the ratio or difference between the distance from the position corresponding to and exceeds a predetermined threshold value, it may be determined that the symmetry of the inclined surface in the convex portion C corresponding to the received light data is defective.

Note that the calculation unit 531 inspects the riblet structure (for example, , the quality of the symmetry of the convex portion C as the shape of the convex portion C may be determined).

In this case, similarly to the above, the computing unit 531 calculates positions corresponding to the second reflected lights RL2-1 and RL2-2 (representative positions of the second reflected light RL2) on the image represented by the intensity distribution data, respectively. is calculated as the incident position of the reflected light.

Then, the calculation unit 531 calculates the difference (interval) between the calculated incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-1, and the calculated second reflected light RL2-1. The riblet structure may be inspected based on the difference (interval) between the incident position of the light RL2-2 on the light receiving surface 3a and the reference incident position of the second reflected light RL2-2.

For example, the computing unit 531 calculates the difference between the incident position of the second reflected light RL2-1 and the reference incident position of the second reflected light RL2-1, and the incident position of the second reflected light RL2-2 and the second reflected light RL2-2. If at least one of the differences from the reference incident position of the light RL2-2 exceeds a predetermined threshold value, it may be determined that the shape of the riblet structure is defective.

It should be noted that the above reference incident position can also be said to be reference data for inspecting the quality of the riblet structure. When the riblet structure has a shape that can be regarded as a non-defective product, the above reference incident position is the second reflected light RL2-1 that is actually reflected by irradiating the object surface OS on which the non-defective riblet structure is formed. and the reference incident position of the second reflected light RL2-2 on the light receiving surface 3a.

Note that the above reference incident position is the reference incident position of the second reflected light RL2-1 on the light receiving surface 3a and the reference position of the second reflected light RL2-2 on the light receiving surface 3a, which are calculated by simulation. It may be the incident position.

Note that the difference between the incident position of the second reflected light RL2-1 and the reference incident position of the second reflected light RL2-1, and the incident position of the second reflected light RL2-2 and the reference of the second reflected light RL2-2 By comparing each difference from the incident position of the second reflected light RL2-1 with a predetermined threshold value, the position of the second reflected light RL2-1 and the second reflected light RL2-1 in the image represented by the intensity distribution data (in other words, the intensity distribution) It can also be said that the riblet structure is inspected by determining whether the position of RL2-2 is included in the reference range of the position of the second reflected light RL2-1 and the position of the second reflected light RL2-2.

The region R may be scraped due to friction with the fluid on the object surface OS, or chipped due to collision with foreign matter. The calculation unit 531 may inspect the quality of the shape of the region R as the shape of the riblet structure.

For example, based on the data representing the intensity distribution of the light condensed by the condensing optical system 2 output from the light receiving element 3 (data based on the reflected light from the riblet structure to be inspected), The quality of the shape of the region R may be inspected.

In this case, the calculation unit 531 may determine the quality of the shape of the region R by comparing the data representing the intensity distribution with the data representing the reference intensity distribution. The data representing the reference intensity distribution can also be said to be reference data for inspecting the quality of the riblet structure.

When the region R has a shape that can be regarded as a non-defective product, the above reference intensity distribution is obtained by actually irradiating the object surface OS on which the convex portion C and the region R of the non-defective product are formed, and reflecting the reflected light. It may be the intensity distribution data of the reference by. The reference intensity distribution data may be calculated by simulation such as a ray tracing method.

Note that the calculation unit 531 may determine the quality of the shape of the region R using any of the processes described above for determining the quality of the shape of the riblet structure (the quality of the shape of the convex portion C). Note that the calculation unit 531 determines the quality of the shape of the convex portion C and the shape of the region R by using any of the processes described above for determining the quality of the shape of the riblet structure (the quality of the shape of the convex portion C). You may judge the quality of

It should be noted that the region R may be clogged with foreign matter. The shape of the region R may include a shape changed due to clogging with foreign matter.

The calculation unit 531 compares the data representing the intensity distribution output from the light receiving element 3 (data based on the reflected light from the riblet structure to be inspected) with at least one of the non-defective product standard data and the defective product standard data. , the quality of the riblet structure may be inspected. The calculation unit 531 compares the data representing the intensity distribution output from the light receiving element 3 with at least one of the non-defective product reference data and the defective product reference data, thereby obtaining the object surface OS as an inspection of the quality of the riblet structure. The quality of the shape of the convex portion C may be determined.

The non-defective item reference data is the light reflected by the irradiation of the light onto the object surface OS having the riblet structure (the convex portion C and the region R) determined to be a non-defective item (the first reflected light RL1, the second reflected light RL2-1, and the (at least one light of the second reflected light RL2-2). The defective product reference data is the reflected light (first reflected light RL1, second reflected light RL2-1 , and at least one of the second reflected light RL2-2).

At least one of the at least one non-defective product reference data and at least one defective product reference data can also be said to be reference data for inspecting the quality of the riblet structure. At least one of the at least one non-defective item criteria data and the at least one defective item criteria data may be stored in the memory 52 in advance.

For example, the non-defective item reference data includes data representing the intensity distribution of light reflected by irradiating light onto the object surface OS having the convex portion C determined to be non-defective because of the rounded apex of the convex portion C. You can stay. For example, the non-defective item reference data is applied to the object surface OS having the convex portion C determined to be non-defective due to the symmetry of the shape of the convex portion C (symmetry of the inclined surface T1 and the inclined surface T2 with respect to the third direction D3). may include data representing the intensity distribution of the light reflected by the irradiation of the light. For example, the non-defective item reference data includes data representing the intensity distribution of the light reflected by the irradiation of the light onto the object surface OS having the convex portion C for which the apex angle A as the shape of the convex portion C is determined to be non-defective. You can stay. For example, the non-defective item reference data includes data representing the intensity distribution of the light reflected by the irradiation of the light onto the object surface OS having the convex portion C determined as the non-defective product with the height H as the shape of the convex portion C. You can stay. For example, the non-defective item reference data is the intensity distribution of the light reflected by the irradiation of the light onto the object surface OS having the convex portion C for which the interval P in the second direction D2 as the shape of the convex portion C is determined to be non-defective. It may contain representative data.

The calculation unit 531 compares the data representing the intensity distribution output from the light-receiving element 3 with the non-defective product reference data described above to determine the shape of the convex portion C such that the vertices of the convex portion C are rounded or convex. At least one of the symmetry of the portion C, the apex angle A of the convex portion C, the height H of the convex portion C, and the interval P of the convex portion C in the second direction D2 may be determined. For example, if the data representing the intensity distribution output from the light-receiving element 3 and the non-defective product criterion data are different (that is, the intensity distribution output from the light-receiving element 3 and the intensity represented by the non-defective product criterion data) distribution), the shape of the convex portion C may be judged to be defective.

As with the non-defective product standard data, the defective product standard data includes, as the shape of the convex portion C, roundness of the apex of the convex portion C, symmetry of the convex portion C, apex angle A of the convex portion C, convexity Intensity distribution of the light reflected by the irradiation of the light onto the object surface OS having the convex portion C for which the height H of the convex portion C and the interval P of the convex portion C in the second direction D2 are determined to be defective respectively. may include data representing

The calculation unit 531 compares the data representing the intensity distribution output from the light receiving element 3 with the above-described defective product reference data to determine the roundness of the apex of the convex portion C as the shape of the convex portion C, At least one of the symmetry of the convex portion C, the apex angle A of the convex portion C, the height H of the convex portion C, and the interval P of the convex portion C in the second direction D2 may be determined. . For example, when the data representing the intensity distribution output from the light receiving element 3 and the above-described defective product reference data are the same (that is, the intensity distribution output from the light receiving element 3 and the defective product reference data are If the intensity distribution shown is the same), it may be determined that the shape of the convex portion C is defective.

Note that the calculation unit 531 calculates the position of the area corresponding to the first reflected light RL1 and the area corresponding to the second reflected light RL2 in the data representing the intensity distribution output from the light receiving element 3 (on the image represented by the intensity distribution data). , and create a luminance profile that represents the luminance of pixels along the virtual line HL1. Then, the calculation unit 531 compares the brightness profile created using the received light data with the brightness profile similarly created from the non-defective product reference data and/or the brightness profile similarly created from the defective product reference data. , the quality of the shape of the convex portion C may be determined.

The non-defective product reference data and the defective product reference data are data representing the intensity distribution output when the optical device 1 of the present embodiment actually irradiates the object surface OS having the riblet structure whose shape is judged in advance with light. is. Also, the non-defective product reference data and the defective product reference data may be data calculated using a simulation using a ray tracing method or the like, for example. For example, the non-defective product reference data and the defective product reference data represent the intensity distribution of the reflected light that is collected when it is assumed that the object surface OS having the riblet structure whose shape has been determined in advance is irradiated with light. It may be simulation data that represents.

The calculation unit 531 supplies data representing the intensity distribution output from the light receiving element 3 (data from the riblet structure to be inspected) to a discriminator that is pre-learned to determine the quality of the shape of the riblet structure represented by the input data. Data based on reflected light) may be input to determine whether the shape of the riblet structure on the object surface OS is good or bad.

The discriminator can be, for example, a convolutional neural network (hereinafter referred to as "CNN") having multiple convolutional layers connected in series from the input side to the output side. A large number of non-defective product reference data and a large number of defective product reference data are used as teacher data and input to the CNN for pre-learning, so that the CNN operates as a discriminator that determines the quality of the shape of the riblet structure.

The discriminator receives data representing the intensity distribution output from the light-receiving element 3 (data based on reflected light from the riblet structure to be inspected) to determine the shape of the convex portion C symmetry of the convex portion C, the vertex angle A of the convex portion C, the height H of the convex portion C, and the interval P of the convex portion C in the second direction D2. It may be learned in advance so as to output the determination result.

The calculation unit 531 inputs the data representing the intensity distribution output from the light receiving element 3 to the discriminator, and calculates the roundness of the apex of the convex portion C and the symmetry of the convex portion C, which are output from the discriminator. , the apex angle A of the convex portion C, the height H of the convex portion C, and the interval P of the convex portion C in the second direction D2. It can be said that the calculation unit 531 determines whether the shape of the convex portion C is good or bad by acquiring the above-described good/bad judgment result.

The discriminator is learned to determine the quality of the shape of the region R by inputting data representing the intensity distribution output from the light receiving element 3 (data based on reflected light from the riblet structure to be inspected). may be The calculation unit 531 inputs the data representing the intensity distribution output from the light receiving element 3 (data based on the reflected light from the riblet structure to be inspected) to the above-described discriminator, so that the region R is output from the discriminator. You may acquire the quality determination result of the shape of .

Based on the distance between the position of the first reflected light RL1 (on the image represented by the intensity distribution data) and the reference position RP in the data representing the intensity distribution output from the light receiving element 3, the detection unit 532 detects the concentration with respect to the object surface OS. A relative inclination of the optical axis AX of the optical optical system 2 may be detected.

The reference position RP is incident parallel to the optical axis AX of the condensing optical system 2, and is aligned with the normal direction of the object surface OS (for example, the normal direction of the region R) and the optical axis AX of the condensing optical system 2. are parallel, the position on the light-receiving surface 3a where the light reflected once by the object surface OS (for example, by the region R) is collected by the collecting optical system 2. FIG.

The condensing optical system 2 is installed on the reference plane so that the optical axis AX is perpendicular to the reference plane. The reference position RP can be a position on the light-receiving surface 3 a at which light irradiated perpendicularly to the reference surface is condensed by the condensing optical system 2 . For example, the reference position RP can be set using a collimator.

FIG. 11 is a schematic diagram showing the second received light data.

In the second received light data RD2 (on the image represented by the intensity distribution data), which is another example of received light data, the first reflected light RL1, the second reflected lights RL2-1, and RL2-2 are positioned along the virtual line HL2. is represented by The virtual line HL2 is separated from the reference position RP by the interval G1. That is, the first reflected light RL1 appears at a position spaced apart from the reference position RP by the interval G1. Also, the pair of second reflected lights RL2-1 and RL2-2 are represented at positions separated from each other by a gap G2.

The detection unit 532 detects that the optical axis AX of the condensing optical system 2 is larger with respect to the object surface OS as the distance G1 between the position of the first reflected light RL1 and the reference position RP on the image represented by the intensity distribution data is larger. Tilting may also be detected.

Note that the relationship between the interval G1 and the inclination of the optical axis AX of the condensing optical system 2 with respect to the object surface OS may be obtained in advance. In this case, the detection unit 532 detects the distance G1 between the position of the first reflected light RL1 and the reference position RP on the image represented by the intensity distribution data. A slope may be calculated.

Further, the detection unit 532 detects the tilt direction of the optical axis AX of the light collecting optical system 2 with respect to the object surface OS according to the position of the first reflected light RL1 with respect to the reference position RP on the image represented by the intensity distribution data. may

In the second received light data RD2 (on the image represented by the intensity distribution data), the first reflected light RL1 is perpendicular to the reference position RP and the imaginary line HL2 perpendicular to the first direction D1 in which the convex portions C continue on the object surface OS. are spaced apart in the direction of At this time, the detection unit 532 may detect that the optical axis of the condensing optical system 2 is tilted along the first direction D1 with respect to the object surface OS. That is, the detection unit 532 may detect the direction in which the optical axis of the condensing optical system 2 is tilted with respect to the object surface OS.

Note that the above-described processing of the detection unit 532 may be executed by the calculation unit 531. Note that the optical device 1 may not include the detection section 532 .

The measurement unit 533 measures a surface to be measured having a riblet structure. The object surface OS is an example of a surface to be measured by the measuring unit 533 . The measurement unit 533 outputs a value regarding the shape of the riblet structure that the object surface OS has, based on the received light data corresponding to the object surface OS.

The received light data corresponding to the object surface OS is reflected by the irradiation area IR by irradiating the irradiation area IR of the object surface OS with the light from the condensing optical system 2, and is condensed by the condensing optical system 2. is data representing the result of receiving light (for example, at least one of the first reflected light RL1 and the second reflected light).

The data representing the result of light reception can also be said to be data representing the intensity distribution of the light condensed by the condensing optical system 2 (for example, at least one of the first reflected light RL1 and the second reflected light). Note that the data representing the intensity distribution may be two-dimensional image data.

The data representing the intensity distribution output from the light receiving element 3 can also be said to be data based on reflected light from the riblet structure to be measured. The light receiving element 3 may be an element such as a line sensor having one-dimensionally arranged pixels, and the data representing the intensity distribution may be one-dimensional image data.

That is, the measurement unit 533 measures the riblet structure based on the intensity distribution data output from the light receiving element 3.

The measurement unit 533 may calculate a value related to the shape of the riblet structure as the measurement of the riblet structure based on the intensity distribution data output from the light receiving element 3 . For example, the measurement unit 533 measures the apex angle A of the convex portion C, the height H of the convex portion C, the radius of curvature at the vertex of the convex portion C, the vertex of the convex portion C, and A value representing at least one of the curvature of and the spacing P of the convex portions in the second direction may be calculated.

The measurement unit 533 calculates the distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2 on the light receiving surface 3a of the light receiving element 3, and based on the calculated distance, A value for the shape of the riblet structure may be calculated. For example, the measuring unit 533 calculates the convex portion as a value related to the shape of the riblet structure based on the calculated distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2. A value representing the apex angle A of C may be calculated.

The distance between the incident position of the second reflected light RL2-1 that is reflected by the irradiation region IR by the light irradiation and is incident on the light receiving surface 3a and the incident position of the second reflected light RL2-2 is the apex angle of the convex portion C It increases as A increases. Therefore, the apex angle A of the convex portion C can be calculated based on the distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2 incident on the light receiving surface 3a. .

The measurement unit 533, similarly to the processing of the calculation unit 531 described above, corresponds to the second reflected light RL2-1 in the data representing the intensity distribution output from the light receiving element 3 (on the image represented by the intensity distribution data). A region corresponding to the region and the second reflected light RL2-2 is specified. For example, the measurement unit 533 extracts pixels whose luminance values are equal to or greater than a predetermined threshold value on the image represented by the intensity distribution data, and clusters and groups the extracted pixels so that the intensity distribution data represents A region corresponding to the second reflected light RL2-1 and a region corresponding to the second reflected light RL2-2 may be specified on the image. Note that the measurement unit 533 may use template matching to identify the area corresponding to the second reflected light RL2-1 and the area corresponding to the second reflected light RL2-2 on the image represented by the intensity distribution data. good.

In the same manner as the processing of the calculation unit 531 described above, the measurement unit 533 measures the area corresponding to the second reflected light RL2-1 and the area corresponding to the second reflected light RL2-2 on the image represented by the specified intensity distribution data. At least one of the position of the pixel having the maximum luminance and the position of the geometrical center of gravity of the area is calculated as the representative position of the reflected light. Note that the position corresponding to the second reflected light RL2-1 (representative position of the second reflected light RL2-1) on the image represented by the intensity distribution data calculated by the measurement unit 533 corresponds to the second position on the light receiving surface 3a. It represents the incident position of the reflected light RL2-1. Further, the position corresponding to the second reflected light RL2-2 (representative position of the second reflected light RL2-2) on the image represented by the intensity distribution data calculated by the measurement unit 533 is the second position on the light receiving surface 3a. It represents the incident position of the reflected light RL2-2.

Then, the measuring unit 533, in the same manner as the above-described processing of the computing unit 531, determines the position corresponding to the second reflected light RL2-1 (second reflected light RL2-1 representative position) and the position corresponding to the second reflected light RL2-2 (representative position of the second reflected light RL2-2), on the image represented by the intensity distribution, corresponding to the second reflected light RL2-1 and the position corresponding to the second reflected light RL2-2 is calculated.

Note that the distance between the position corresponding to the second reflected light RL2-1 and the position corresponding to the second reflected light RL2-2 on the image represented by the intensity distribution is the second reflected light RL2-1 on the light receiving surface 3a. and the incident position of the second reflected light RL2-2. The interval between the position corresponding to the second reflected light RL2-1 and the position corresponding to the second reflected light RL2-2 on the image represented by the intensity distribution is represented by the interval G2 in FIG. 11, for example. interval.

Further, relational data between the distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2 incident on the light receiving surface 3a and the apex angle A of the convex portion C is obtained in advance. You can leave it. The relationship data between the interval of the second reflected light RL2 and the apex angle A of the convex portion C may be function data or table data such as a lookup table.

The relationship data between the interval of the second reflected light RL2 and the apex angle A of the convex portion C can be said to be reference data for measuring the riblet structure. Reference data for measuring the riblet structure may be stored in memory 52 . The reference data for measuring the riblet structure can also be said to be reference data for measuring the riblet structure.

The measurement unit 533 combines the calculated distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2 and the reference data for measuring the riblet structure into the reference data for measuring the riblet structure. , a value representing the apex angle A of the convex portion C may be calculated as a value relating to the shape of the riblet structure. For example, the measurement unit 533 refers to the reference data for measuring the riblet structure, and determines the height of the convex portion C corresponding to the distance between the incident position of the second reflected light RL2-1 and the incident position of the second reflected light RL2-2. A value representing the apex angle A may be calculated.

It should be noted that the target to be measured by the measuring unit 533 (target for calculating the value related to the shape) is not limited to the apex angle A of the convex portion C. For example, the measurement unit 533 obtains the height H of the convex portion C, the radius of curvature of the vertex of the convex portion C, the curvature of the vertex of the convex portion C, and the second At least one value of the interval P between the convex portions C in the direction D2 may be calculated.

Note that the measurement unit 533 may also measure the riblet structure using the intensity of the light emitted from the light source LS, which is output from the light intensity measuring device described above.

Note that the measurement unit 533 is not limited to the distance between the second reflected light RL2-1 and the second reflected light RL2-2 on the light receiving surface 3a, and the distance between the first reflected light RL1, the second reflected light RL2-1, and the second reflected light RL2-1 A value related to the shape of the riblet structure may be calculated based on the distance between the incident position of the two reflected lights 2-2 on one light receiving surface 3a and the incident position on the other light receiving surface 3a.

In addition, in the same manner as described above, the reference data for measuring the riblet structure (the light receiving surface of one of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2) Data relating to the distance between the position of incidence on 3a and the position of incidence on the other light-receiving surface 3a and the shape of the riblet structure may be obtained in advance. In this case, the measurement unit 533 measures the incident positions of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2 on one of the light receiving surfaces 3a and the other light receiving surface 3a. A value for the shape of the riblet structure may be calculated based on the distance between the positions of incidence on the beam and reference data for measuring the riblet structure. It should be noted that the processing of the calculation unit 531 or the measurement unit 533 described above can be used for the processing related to the calculation of the interval between the incident positions of the reflected light.

Note that the measurement unit 533 measures the shape of the riblet structure based on the incident position of at least one of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2 on the light receiving surface 3a. may be calculated.

Incidentally, in the same manner as described above, the reference data for measuring the riblet structure (at least one of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2 is incident relationship data between the position and the shape of the riblet structure) may be obtained. In this case, the measurement unit 533 determines the incident position of at least one of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2, and the reference data for measuring the riblet structure. A value for the shape of the riblet structure may be calculated based on . Note that the processing of the calculation unit 531 or the measurement unit 533 described above can be used for the processing related to the calculation of the incident position of the reflected light.

Note that the measurement unit 533 measures the intensity of the riblet structure based on the intensity of at least one of the first reflected light RL1, the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2. A value for the shape may be calculated.

Note that reference data for measuring the riblet structure (first reflected light RL1, first reflected light RL1, second reflected light RL2-1, and second reflected light 2-2 and relationship data between the intensity of at least one light and the shape of the riblet structure). In this case, the measurement unit 533 measures the intensity of at least one of the first reflected light RL1, the second reflected light RL2-1, and the second reflected light 2-2, and the reference data for measuring the riblet structure. A value for the shape of the riblet structure may be calculated based on . Note that the above-described processing of the calculation unit 531 can be used for the processing related to the calculation of the intensity of the reflected light.

The measurement unit 533 may calculate a value related to the shape of the riblet structure by comparing data representing the intensity distribution output from the light receiving element 3 and a plurality of shape reference data. The plurality of shape reference data are the light reflected by irradiation of light onto the object surface OS having a plurality of riblet structures each having a different shape (for example, the first reflected light RL1, the second reflected light RL2-1, and the second reflected light RL2-1). (at least one of the reflected light RL2-2). A plurality of shape reference data are stored in the memory 52 in advance.

For example, the measurement unit 533 determines, among the plurality of shape reference data, data (shape reference The intensity distribution represented by the data) may be specified, and the value of the shape corresponding to the specified data may be calculated.

It should be noted that the plurality of shape reference data can also be said to be reference data for measuring the riblet structure. For example, the plurality of shape reference data are the apex angle A of the convex portion C, the height H of the convex portion C, the radius of curvature of the vertex of the convex portion C, and the vertex of the convex portion C as the shape of the riblet structure. and the distance P between the convex portions C in the second direction D2, and the light reflected by the irradiation of the light onto the object surface OS having a plurality of riblet structures (for example, the first reflection It may be a plurality of data representing the intensity distribution of at least one of the light RL1, the second reflected light RL2-1, and the second reflected light RL2-2.

The measurement unit 533 compares the data representing the intensity distribution output from the light receiving element 3 with a plurality of shape reference data to determine the apex angle A of the convex portion C and the shape of the convex portion C as the shape of the riblet structure. At least one of the height H, the radius of curvature of the apex of the convex portion C, the curvature of the apex of the convex portion C, and the interval P of the convex portion C in the second direction D2 may be calculated.

The shape reference data described above represents the intensity distribution of the light reflected by the object surface OS and condensed by the condensing optical system 2 by actually irradiating the object surface OS having the riblet structure of a predetermined shape with light. Data. Also, the shape reference data may be data calculated using a simulation using a ray tracing method or the like, for example. For example, the shape reference data may be simulation data representing the intensity distribution of reflected light that is condensed when it is assumed that an object surface OS having a riblet structure with a predetermined shape is irradiated with light. A plurality of shape reference data may be created by obtaining data representing the intensity distribution when the shape of the riblet structure is changed through simulation.

The measurement unit 533 inputs the data representing the intensity distribution output from the light receiving element 3 to a discriminator that is pre-learned to output a value related to the shape of the riblet structure of the object surface OS represented by the input data. may output a value for the shape of the riblet structure. A discriminator may be, for example, a CNN. Shape reference data corresponding to various shapes of the riblet structure and values related to the shape of the riblet structure corresponding to each shape reference data are used as teacher data, and input to the CNN for pre-learning. It works as a discriminator that outputs a shape-related value.

For example, the discriminator receives data representing the intensity distribution output from the light receiving element 3, and obtains the apex angle A of the convex portion C, the height H of the convex portion C, and the convex shape as the shape of the riblet structure. It may be learned in advance so as to output a calculation result of at least one of the radius of curvature of the vertex of the portion C, the curvature of the vertex of the convex portion C, and the interval P of the convex portion C in the second direction D2. . The measurement unit 533 inputs the data representing the intensity distribution output from the light receiving element 3 to the discriminator, and measures the apex angle A of the convex portion C and the height of the convex portion C, which are output from the discriminator. H, the radius of curvature of the vertex of the convex portion C, the curvature of the vertex of the convex portion C, and the interval P of the convex portion C in the second direction D2 are calculated. It can be said that the measurement unit 533 has calculated a value related to the shape of the riblet structure by obtaining the calculation result.

Note that the processing related to the measurement of the riblet structure described above by the measurement unit 533 may be executed by the calculation unit 531 . For example, the measurement unit 533 may also function as the calculation unit 531 . In this case, the calculation unit 531 may perform the processing related to the measurement of the riblet structure described above. For example, the computing unit 531 may perform the above-described processing regarding riblet structure measurement in addition to the above-described processing regarding riblet structure inspection. For example, the computing unit 531 may calculate a value related to the shape of the riblet structure as a process related to the above-described measurement of the riblet structure in addition to the above-described process related to the inspection of the riblet structure. Note that the calculation unit 531 may calculate a value related to the shape of the riblet structure as the inspection result of the riblet structure. Note that the calculation unit 531 may perform the above-described processing of detecting the inclination of the optical axis AX of the condensing optical system 2 with respect to the object surface OS by the detection unit 532 .

It should be noted that the processing related to inspection of the riblet structure described above by the calculation unit 531 may be executed by the measurement unit 533 . Note that the measurement unit 533 may perform the above-described processing related to detection of the inclination of the optical axis AX of the condensing optical system 2 with respect to the object surface OS by the detection unit 532 .

FIG. 12 is a flow chart of the riblet structure inspection process. The optical device 1 performs inspection processing of the object surface OS on which the riblet structure is formed according to the following flowchart.

The optical device 1 irradiates a surface to be inspected (object surface OS) having a riblet structure with light from the condensing optical system 2 (step S11).

Next, the optical device 1 collects the first reflected light RL1 reflected once by the region R where the convex portion C is not provided in the irradiation region IR and the inclined surface of the convex portion C by the light collecting optical system 2. The second reflected light RL2 that has been reflected at least once by T and the region R is condensed (step S12).

Next, the optical device 1 receives the condensed light with the light-receiving element 3 arranged on a surface different from the surface conjugated to the surface to be inspected with respect to the condensing optical system 2 (step S13).

Then, the computer 5 communicably connected to the optical device 1 inspects the riblet structure (surface to be inspected) based on the light reception result (data representing the intensity distribution) (step S14), and ends the inspection process. For example, as described above, the computer 5 (calculation unit 531) determines whether the shape of the riblet structure is good or bad.

By executing the inspection process in this manner, the optical device 1 can easily inspect the riblet structure.

The processor 53 included in the computer 5 communicably connected to the optical device 1 may not have some of the functional blocks of the computing section 531, the detecting section 532, and the measuring section 533. For example, by providing the computer 5 with the processor 53 having at least the measurement unit 533 as a functional block, the optical device 1 can operate as a device for measuring the riblet structure formed on the surface of the object. For example, by providing the computer 5 with the processor 53 having at least the arithmetic unit 531 as a functional block, the optical device 1 can operate as a device for inspecting the riblet structure formed on the surface of the object.

FIG. 13 is a flow chart of the riblet structure measurement process. The optical device 1 performs measurement processing of the riblet structure formed on the object surface OS according to the following flowchart.

In the flow chart of the riblet structure measurement process, steps S21-S23 are the same as steps S11-S13 of the riblet structure inspection process, so description thereof will be omitted.

Following step S23, the computer 5 communicably connected to the optical device 1 measures the riblet structure based on the result of light reception (data representing the intensity distribution) (step S24), and ends the measurement process. For example, as described above, computer 5 (measuring unit 533) calculates values for the shape of the riblet structure.

By executing the measurement process in this way, the optical device 1 can easily measure the riblet structure.

Note that the optical device 1 described above may be attached to a movable body. Movable bodies include, for example, robots such as vertical articulated robots, gimbals, manned/unmanned aircraft, and manned/unmanned vehicles. In this case, the movable body on which the optical device 1 is mounted positions the optical device 1 with respect to the object surface OS, the above-described inspection of the riblet structure, the measurement of the riblet structure, and the optical device 1 (focusing) on the object surface OS. At least one detection of the tilt of the optical system 2) may be performed. For example, the contact member 4a of the optical device 1 is brought into contact (positioned) with the object surface OS by a movable body, and the above-described riblet structure inspection, the riblet structure measurement, and the optical device 1 with respect to the object surface OS are performed. may perform at least one of detection of the inclination of .

Note that the contact member 4a of the optical device 1 does not have to contact the object surface OS. For example, the optical device 1 is positioned so that the contact member 4a is located away from the object surface OS with a movable body, and the above-described inspection of the riblet structure, measurement of the riblet structure, and measurement of the object surface OS are performed. At least one of detecting the tilt of the optical device 1 may be performed. In this case, the optical device 1 may not include the contact member 4a.

At least one of the inspection of the riblet structure, the measurement of the riblet structure, and the detection of the inclination of the optical device 1 with respect to the object surface OS is performed by the optical device 1 while the optical device 1 is moved on the object surface OS by the movable body. You can run one.

Note that the optical device 1 described above does not have to be attached to the movable body. For example, an operator may position a hand-held optical device 1 (e.g., housing 4) relative to the object surface OS and use the optical device 1 to inspect the riblet structure, measure the riblet structure, and measure the object surface OS as described above. At least one detection of the tilt of the optical device 1 (condensing optical system 2) with respect to may be performed.

For example, the operator brings the abutting member 4a of the optical device 1 held by hand into contact with the object surface OS to perform the above-described inspection of the riblet structure, measurement of the riblet structure, and inclination of the optical device 1 with respect to the object surface OS. at least one of the detection of

Note that the contact member 4a of the optical device 1 does not have to contact the object surface OS. For example, the operator positions the optical device 1 held by hand so that the abutment member 4a is located away from the object surface OS, and uses the optical device 1 to inspect the riblet structure described above. and/or detecting the tilt of the optical device 1 with respect to the object surface OS. In this case, the optical device 1 may not include the contact member 4a.

While moving the optical device 1 held by hand over the object surface OS, the operator uses the optical device 1 to inspect the riblet structure, measure the riblet structure, and measure the inclination of the optical device 1 with respect to the object surface OS. At least one of detection may be performed.

At least one of inspection and measurement of the riblet structure may be performed using the optical device 1 described above and another optical device. For example, the optical device 1 and a white interference microscope as another optical device may be used to inspect and measure the riblet structure. In this case, the optical device 1 inspects the riblet structure as described above (for example, symmetry of the convex portion C) and measurement of the riblet structure (for example, calculation of the apex angle A of the convex portion C). The white light interference microscope inspects the riblet structure (for example, determines the quality of the interval P between the convex portions C), and At least one of the measurement of the riblet structure (for example, the calculation of the height H of the convex portion C) may be performed.

The other optical device is not limited to a white interference microscope, and may be a confocal microscope or other existing device capable of at least one of inspection and measurement of objects.

In the above description, the optical device 1 inspects and/or measures the riblet structure formed on the surface of the workpiece. However, the optical device 1 may inspect and/or measure any structure having any shape formed on the surface of the workpiece.

An example of an arbitrary structure is a structure that generates a vortex in the fluid flow on the work surface. Another example of the arbitrary structure is a structure for imparting hydrophobicity to the work surface. Another example of the arbitrary structure is a regularly or irregularly formed micro/nanometer-order fine texture structure (typically, an uneven structure including a mountain structure and a groove structure).

The fine texture structure may include at least one of a shark-skin structure and a dimple structure that have the function of reducing fluid (gas and/or liquid) resistance. The microtextured structure may comprise a lotus leaf surface structure having at least one of a liquid-repellent function and a self-cleaning function (eg, having a lotus effect).

The fine texture structure includes a fine projection structure having a liquid transport function (see US Patent Publication No. 2017/0044002), a concave-convex structure having a lyophilic function, a concave-convex structure having an antifouling function, a reflectance reducing function and a repellent structure. A moth-eye structure having at least one of liquid functions, a concavo-convex structure that enhances only light of a specific wavelength by interference to exhibit a structural color, a pillar array structure that has an adhesive function using van der Waals force, a concavo-convex structure that has an aerodynamic noise reduction function, A honeycomb structure that has a droplet collection function, an uneven structure that improves adhesion with the layer formed on the surface, an uneven structure that reduces frictional resistance, an uneven structure that reduces icing, etc. At least one may be included.

Also in this case, the convex structures forming the concave-convex structure may have the same structure as the convex portions forming the riblet structure described above. The groove structure forming the uneven structure may have the same structure as the region R forming the riblet structure described above. Note that the fine textured structure does not have to have a specific function.

Regarding the above-described embodiment, the following additional remarks are disclosed.

[Appendix A1]
An optical device for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
a condensing optical system for irradiating an irradiation area on the surface to be inspected with light from a light source and condensing the light reflected by the irradiation area;
a light-receiving element arranged on a surface different from a surface conjugated to the surface to be inspected with respect to the condensing optical system and configured to receive the light condensed by the condensing optical system;
An optical device comprising

[Appendix A2]
The optical device according to appendix A1, wherein the light receiving element has a light receiving surface arranged on a plane different from the conjugate plane, and detects an intensity distribution of the light condensed by the condensing optical system.

[Appendix A3]
The optical device according to appendix A2, wherein the condensing optical system satisfies the following conditional expression.
γ > β
however,
β: the angle formed between the normal line at the end of the effective range of the lens surface closest to the surface to be inspected in the condensing optical system and the optical axis of the condensing optical system γ: the condensing optical system The maximum angle formed by the light beam received by the light receiving element and the optical axis of the condensing optical system among the light beams incident on the lens arranged closest to the surface to be inspected in

[Appendix A4]
The optical device according to appendix A2 or A3, wherein the condensing optical system satisfies the following conditional expression.
y < f sin θ
however,
y: the radius of a circle circumscribing the range of light condensed on the light receiving surface by the condensing optical system f: the focal length of the condensing optical system θ: the light reflected by the irradiation area and the condensing optics angle with the optical axis of the system

[Appendix A5]
The optical device according to any one of Appendices A2 to A4, further comprising a computing unit that inspects the riblet structure based on data representing the intensity distribution detected by the light receiving element.

[Appendix A6]
The optical device according to appendix A5, wherein the calculation unit inspects the riblet structure by comparing data representing the intensity distribution output from the light receiving element with pre-stored reference data of the intensity distribution.

[Appendix A7]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The computing unit includes a position of each of the first reflected light and the second reflected light in the intensity distribution included in a previously stored reference range of positions of the first reflected light and the second reflected light. Optical apparatus according to Appendix A5 or A6, inspecting the riblet structure by determining whether the riblet structure is

[Appendix A8]
An inspection method for inspecting a riblet structure based on data representing the intensity distribution output from the optical device according to any one of Appendices A2-A7.

[Appendix A9]
The inspection method according to Appendix A8, wherein the inspecting includes determining the quality of the shape of the convex portion as the inspection of the riblet structure based on the data representing the intensity distribution.

[Appendix A10]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light reflected twice by the portion not provided and the convex portion;
The inspecting determines whether the shape of the convex portion is good or bad based on a comparison result between the intensity of the first reflected light incident on the light receiving surface and the intensity of the second reflected light incident on the light receiving surface. The inspection method of Appendix A9, comprising determining.

[Appendix A11]
The inspection method according to Appendix A10, wherein the shape of the convex portion includes a rounded vertex of the convex portion.

[Appendix A12]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The second reflected light includes second reflected light reflected in a second reflection direction different from the first reflection direction in which the first reflected light is reflected from the irradiation area, and second reflection light reflected from the irradiation area in the first reflection direction. and a second reflected light reflected in a third reflection direction different from the second reflection direction,
The inspecting includes the distance between the incident position of the first reflected light on the light receiving surface and the incident position of the second reflected light reflected in the second reflection direction, and the distance between the incident position of the second reflected light on the light receiving surface and the second Supplementary notes A9-A11, including determining the quality of the shape of the convex portion based on the distance between the incident position of the first reflected light and the incident position of the second reflected light reflected in the third reflection direction. The inspection method according to any one of the items.

[Appendix A13]
the convex portion has a pair of inclined surfaces that are inclined with respect to a third direction orthogonal to the first direction and the second direction and extend in the first direction;
The inspection method according to Appendix A12, wherein the shape of the convex portion includes symmetry between one inclined surface and the other inclined surface of the pair of inclined surfaces.

[Appendix A14]
The inspecting includes data representing the intensity distribution output from the light receiving element, at least one non-defective product reference data representing the intensity distribution of light reflected by irradiation of light to the convex portion of the shape of a non-defective product, and The quality of the shape of the convex portion of the defective product is determined by comparing with at least one of at least one of the defective product reference data representing the intensity distribution of the light reflected by the irradiation of light to the convex portion of the shape of the defective product. The inspection method according to any one of Appendices A9-A13, comprising:

[Appendix A15]
The inspecting includes inputting data representing the intensity distribution to a discriminator that has been pre-learned to determine the quality of the shape of the convex portion, thereby determining the quality of the shape of the convex portion. The inspection method according to any one of Appendices A9-A14, comprising:

[Appendix A16]
The inspecting includes calculating a value related to the shape of the convex portion based on data representing the intensity distribution detected by the light receiving element. Inspection method.

[Appendix A17]
Appendices A8 to A16, wherein the inspecting includes inspecting the riblet structure by comparing data representing the intensity distribution output from the light receiving element with reference data of the intensity distribution stored in advance. The inspection method according to any one of the items.

[Appendix A18]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
In the inspecting, the position of each of the first reflected light and the second reflected light in the intensity distribution falls within a pre-stored reference range of the positions of the first reflected light and the second reflected light. The inspection method of any one of Appendices A8-A17, comprising inspecting the riblet structure by determining whether it is included.

[Appendix B1]
An inspection method for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
irradiating an irradiation area on the surface to be inspected with light;
Condensing the light reflected by the irradiation area by the irradiation of the light with a condensing optical system;
Receiving the condensed light on a plane different from a plane conjugated to the surface to be inspected with respect to the condensing optical system;
inspecting the riblet structure based on the results of receiving light;
inspection methods including;

[Appendix B2]
In the light reception, a light-receiving element having a light-receiving surface arranged on a plane different from the conjugate plane receives the condensed light, and the light-receiving element receives the condensed light as a result of the light reception. The inspection method according to appendix B1, wherein an intensity distribution is detected.

[Appendix B3]
The inspection method according to Appendix B2, wherein the condensing optical system has a numerical aperture of 0.7 or more on the surface to be inspected side.

[Appendix B4]
The inspection method according to Appendix B2 or B3, wherein the condensing optical system has a numerical aperture of 0.9 or less on the inspection surface side.

[Appendix B5]
The inspection method according to any one of Appendices B2 to B4, wherein the condensing optical system is arranged closest to the surface to be inspected and includes a lens member having a concave surface facing the surface to be inspected.

[Appendix B6]
further comprising contacting the surface to be inspected with a contact member projecting further toward the surface to be inspected than an optical member arranged closest to the surface to be inspected among the optical members constituting the condensing optical system. , and the inspection method according to any one of Appendices B2-B5.

[Appendix B7]
The inspection method according to Appendix B6, wherein the contact member contacts at least a part of the surface to be inspected excluding the irradiation region.

[Appendix B8]
The contact member and the condensing optical system are configured such that when the contact member contacts the surface to be inspected, the condensing optical system and the surface to be inspected are arranged in the optical axis direction of the condensing optical system. The inspection method according to appendix B6 or B7, wherein the distance between is the working distance of the condensing optical system on the side of the surface to be inspected.

[Appendix B9]
The abutment member has a distance between the converging optical system and the surface to be inspected in the optical axis direction of the converging optical system when the abutting member abuts on the surface to be inspected. The inspection method according to any one of Appendices B6 to B8, wherein at least the optical member arranged closest to the surface to be inspected is supported so that the working distance of the system is on the side of the surface to be inspected.

[Appendix B10]
The light reflected by the irradiation region includes first reflected light reflected once by a region of the irradiation region where the convex portion is not provided, and light reflected by the convex portion and the irradiation region. The inspection method according to any one of Appendices B2 to B9, including the second reflected light reflected twice by the area where the convex portion is not provided.

[Appendix B11]
The condensing optical system reflects at least part of the light from the light source toward the irradiation area, and a part of the first reflected light and the second reflected light that enter the condensing optical system from the irradiation area. The light splitting member according to Appendix B10, which transmits reflected light toward the light receiving element and is configured to prevent another part of the first reflected light different from the part from entering the light receiving element. Inspection method.

[Appendix B12]
The inspection method according to Appendix B11, wherein the light splitting member reflects the other portion of the first reflected light in a direction different from that of the light receiving element.

[Appendix B13]
The light splitting member is configured such that the light amount of the part of the first reflected light emitted from the light splitting member is smaller than the light amount of the other part of the first reflected light emitted from the light splitting member. The inspection method according to Appendix B11 or B12.

[Appendix B14]
The condensing optical system according to any one of Appendices B11 to B13, further comprising a lens member disposed closest to the light splitting member when viewed from the surface to be inspected and having a concave surface facing the light splitting member. Test method described.

[Appendix B15]
The size of the area occupied on the light receiving surface by the light beam incident on the light collecting optical system from one point on the surface to be inspected and reaching the light receiving element at the maximum numerical aperture of the light collecting optical system on the side of the surface to be inspected , the inspection method according to any one of Appendices B2 to B14, wherein the size of the light receiving surface is 0.1 times or more.

[Appendix B16]
of attachments B2 to B15, wherein the light-receiving surface is arranged closer to the exit pupil plane of the light-condensing optical system than an optical member arranged closest to the light-receiving element among optical members constituting the light-condensing optical system The inspection method according to any one of the items.

[Appendix B17]
The inspection method according to any one of Appendices B2 to B16, wherein the light receiving surface is arranged on the exit pupil plane of the condensing optical system or on a plane conjugate with the exit pupil.

[Appendix B18]
The inspection method according to any one of Appendices B2 to B17, wherein the convex portion has an inclined surface inclined with respect to a third direction orthogonal to the first direction and the second direction.

[Appendix B19]
The inspection method according to any one of Appendices B2 to B18, wherein the riblet structure is a structure for reducing frictional resistance between a fluid and the surface to be inspected.

[Appendix B20]
The optical device according to any one of Appendices B2 to B19, wherein the condensing optical system satisfies the following conditional expression.
γ > β
however,
β: the angle formed between the normal line at the end of the effective range of the lens surface closest to the surface to be inspected in the condensing optical system and the optical axis of the condensing optical system γ: the condensing optical system The maximum angle formed by the light beam received by the light receiving element and the optical axis of the condensing optical system among the light beams incident on the lens arranged closest to the surface to be inspected in

[Appendix B21]
The inspection method according to any one of Appendices B2 to B20, wherein the condensing optical system satisfies the following conditional expression.
y < f sin θ
however,
y: image height of the condensing optical system f: focal length of the condensing optical system θ: angle between the light reflected in the irradiation area and the optical axis of the condensing optical system

[Appendix B22]
The inspection method according to any one of Appendices B2 to B21, wherein the inspecting includes inspecting the riblet structure based on data representing the intensity distribution output from the light receiving element.

[Appendix B23]
The inspection method according to Appendix B22, wherein the inspecting includes determining whether the shape of the convex portion is good or bad based on data representing the intensity distribution.

[Appendix B24]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The inspecting determines the quality of the convex portion based on a comparison result between the intensity of the first reflected light incident on the light receiving surface and the intensity of the second reflected light incident on the light receiving surface. The inspection method according to Appendix B23, comprising:

[Appendix B25]
The inspection method according to Appendix B24, wherein the shape of the convex portion includes rounded vertices of the convex portion.

[Appendix B26]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The second reflected light includes second reflected light reflected in a second reflection direction different from the first reflection direction in which the first reflected light is reflected from the irradiation area, and second reflection light reflected from the irradiation area in the first reflection direction. and a second reflected light reflected in a third reflection direction different from the second reflection direction,
The inspecting includes the distance between the incident position of the first reflected light on the light receiving surface and the incident position of the second reflected light reflected in the second reflection direction, and the distance between the incident position of the second reflected light on the light receiving surface and the second Supplementary notes B23-B25, including determining whether the shape of the convex portion is good or bad based on the distance between the incident position of the first reflected light and the incident position of the second reflected light reflected in the third reflection direction. The inspection method according to any one of the items.

[Appendix B27]
the convex portion has a pair of inclined surfaces that are inclined with respect to a third direction orthogonal to the first direction and the second direction and extend in the first direction;
The inspection method according to appendix B26, wherein the shape of the convex portion includes symmetry between one inclined surface and the other inclined surface of the pair of inclined surfaces.

[Appendix B28]
The inspecting includes data representing the intensity distribution output from the light receiving element, at least one non-defective product reference data representing the intensity distribution of light reflected by irradiation of light to the convex portion of the shape of a non-defective product, and The quality of the shape of the convex portion of the defective product is determined by comparing with at least one of at least one of the defective product reference data representing the intensity distribution of the light reflected by the irradiation of light to the convex portion of the shape of the defective product. The inspection method according to any one of Appendixes B23-B27, comprising:

[Appendix B29]
The inspecting is performed by inputting data representing the intensity distribution output from the light receiving element to a discriminator that has been learned in advance to determine whether the shape of the convex portion is good or bad. The inspection method according to any one of Appendices B23-B28, comprising determining whether the shape is good or bad.

[Appendix B30]
The inspecting includes calculating a value related to the shape of the convex portion based on data representing the intensity distribution output from the light receiving element. Inspection method.

[Appendix B31]
Appendices B22-B30, wherein the inspecting includes inspecting the riblet structure by comparing data representing the intensity distribution output from the light receiving element with pre-stored reference data of the intensity distribution. The inspection method according to any one of the items.

[Appendix B32]
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
In the inspecting, the position of each of the first reflected light and the second reflected light in the intensity distribution falls within a pre-stored reference range of the positions of the first reflected light and the second reflected light. The inspection method of any one of Appendixes B22-B31, comprising inspecting the riblet structure by determining whether it is included.

[Appendix B33]
A computer program for inspection, which causes a computer to execute the inspection method according to any one of Appendices B1 to B32.

[Appendix C1]
An optical device for measuring a surface to be measured having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
a condensing optical system that irradiates an irradiation area on the surface to be measured with light from a light source and collects the light reflected by the irradiation area;
a light-receiving element arranged on a surface different from a surface conjugated to the surface to be inspected with respect to the condensing optical system and configured to receive the light condensed by the condensing optical system;
An optical device comprising

[Appendix C2]
The optical device according to appendix C1, wherein the light receiving element has a light receiving surface arranged on a plane different from the conjugate plane, and detects an intensity distribution of the light condensed by the condensing optical system.

[Appendix C3]
The optical device according to appendix C2, wherein the condensing optical system has a numerical aperture of 0.7 or more on the surface to be measured side.

[Appendix C4]
The optical device according to Appendix C2 or C3, wherein the condensing optical system has a numerical aperture of 0.9 or less on the surface to be measured side.

[Appendix C5]
The optical device according to any one of Appendices C2 to C4, wherein the condensing optical system includes a lens member disposed closest to the measurement scan surface and having a concave surface facing the surface to be measured.

[Appendix C6]
further comprising a contact member that protrudes toward the surface to be measured from an optical member arranged closest to the surface to be measured among optical members constituting the condensing optical system and is capable of coming into contact with the surface to be measured. , Appendices C2-C5.

[Appendix C7]
The optical device according to appendix C6, wherein the contact member is capable of contacting at least a part of the surface to be measured excluding the irradiation region.

[Appendix C8]
The contact member and the condensing optical system are configured such that when the contact member contacts the surface to be measured, the condensing optical system and the surface to be measured are arranged in the optical axis direction of the condensing optical system. is the working distance of the condensing optical system on the side of the surface to be measured.

[Appendix C9]
The abutment member has a distance between the converging optical system and the surface to be measured in the optical axis direction of the condensing optical system when the abutting member abuts on the surface to be measured. The optical device according to any one of Appendices C6 to C8, wherein at least the optical member arranged closest to the surface to be measured is supported so that the working distance of the system is on the side of the surface to be measured.

[Appendix C10]
The light reflected by the irradiation region includes first reflected light reflected once by a region of the irradiation region where the convex portion is not provided, and light reflected by the convex portion and the irradiation region. The optical device according to any one of Appendices C2 to C9, further comprising a second reflected light reflected twice by the area where the convex portion is not provided.

[Appendix C11]
The condensing optical system reflects at least part of the light from the light source toward the irradiation area, and a part of the first reflected light and the second reflected light that enter the condensing optical system from the irradiation area. The light splitting member according to Appendix C10, which transmits reflected light toward the light receiving element and is configured to prevent another part of the first reflected light different from the part from entering the light receiving element. optical device.

[Appendix C12]
The optical device according to appendix C11, wherein the light splitting member reflects the other portion of the first reflected light in a direction different from that of the light receiving element.

[Appendix C13]
The light splitting member is configured such that the light amount of the part of the first reflected light emitted from the light splitting member is smaller than the light amount of the other part of the first reflected light emitted from the light splitting member. The optical device according to appendix C11 or C12, wherein

[Appendix C14]
The condensing optical system according to any one of Appendices C11 to C13, further comprising a lens member disposed closest to the light splitting member when viewed from the surface to be measured and having a concave surface facing the light splitting member. Optical device as described.

[Appendix C15]
The size of the area occupied on the light receiving surface by the light beam incident on the light collecting optical system from one point on the surface to be measured and reaching the light receiving element at the maximum numerical aperture of the light collecting optical system on the side of the surface to be measured , which is at least 0.1 times the size of the light receiving surface.

[Appendix C16]
of attachments C2 to C15, wherein the light-receiving surface is arranged closer to the exit pupil plane of the light-condensing optical system than an optical member arranged closest to the light-receiving element among the optical members constituting the light-condensing optical system. An optical device according to any one of the preceding claims.

[Appendix C17]
The optical device according to any one of Appendices C2 to C16, wherein the light receiving surface is arranged on the exit pupil plane of the condensing optical system or on a plane conjugate with the exit pupil.

[Appendix C18]
The optical device according to any one of Appendices C2 to C17, wherein the convex portion has an inclined surface inclined with respect to a third direction perpendicular to the first direction and the second direction.

[Appendix C19]
The optical device according to any one of Appendices C2 to C18, wherein the riblet structure is a structure for reducing frictional resistance between a fluid and the surface to be measured.

[Appendix C20]
The optical device according to any one of Appendices C2 to C19, wherein the condensing optical system satisfies the following conditional expression.
γ > β
however,
β: the angle formed between the normal line at the end of the effective range of the lens surface closest to the surface to be inspected in the condensing optical system and the optical axis of the condensing optical system γ: the condensing optical system The maximum angle formed by the light beam received by the light receiving element and the optical axis of the condensing optical system among the light beams incident on the lens arranged closest to the surface to be inspected in

[Appendix C21]
The optical device according to any one of Appendices C2 to C20, wherein the condensing optical system satisfies the following conditional expression.
y < f sin θ
however,
y: image height of the condensing optical system f: focal length of the condensing optical system θ: angle between the light reflected in the irradiation area and the optical axis of the condensing optical system

[Appendix C22]
The optical device according to any one of Appendices C2 to C21, wherein the light receiving element outputs data representing an intensity distribution of the light condensed on the light receiving surface by the condensing optical system.

[Appendix C23]
The optical device according to any one of Appendix C22, further comprising a measurement unit that measures the riblet structure based on data representing the intensity distribution output from the light receiving element.

[Appendix C24]
The optical device according to appendix C23, wherein the measurement unit calculates a value related to the shape of the riblet structure as the measurement of the riblet structure based on the data representing the intensity distribution output from the light receiving element.

[Appendix C25]
The measurement unit includes data representing the intensity distribution output from the light receiving element, and a plurality of shape reference data representing the intensity distribution of the light reflected by the irradiation of the light to the plurality of riblet structures having different shapes. The optical device according to Appendix C24, wherein the value for the shape of the riblet structure is calculated based on.

[Appendix C26]
The measurement unit inputs the data representing the intensity distribution output from the light receiving element to a discriminator pre-learned so as to calculate a value related to the shape of the riblet structure, thereby obtaining a value related to the shape of the riblet structure. The optical device of clause C24 or C25, which outputs a value.

[Appendix C27]
The optical device according to Appendix C26, wherein the discriminator comprises a convolutional neural network having a plurality of convolutional layers serially connected from an input side to an output side.

[Appendix C28]
The measuring unit selects at least one of the distance between the convex portions in the second direction, the apex angle of the convex portions, the height of the convex portions, and the radius of curvature of the apex of the convex portions as the value. The optical device according to any one of clauses C24-C27, wherein the optical device calculates a value representing the

[Appendix C29]
The light reflected by the irradiation area includes reflected light reflected twice by the convex portion and a region of the irradiation region where the convex portion is not provided,
The reflected light reflected twice includes reflected light reflected from the irradiation area in a first reflection direction and reflected light reflected from the irradiation area in a second reflection direction different from the first reflection direction. including
The measurement unit measures the riblet on the light receiving surface based on the relationship between the incident position of the reflected light reflected in the first reflection direction and the incident position of the reflected light reflected in the second reflection direction. Optical apparatus according to appendices C23-C28, for calculating a value for the shape of a structure.

[Appendix C30]
The optical device according to Appendix C29, wherein the value for the shape of the riblet structure is a value representing the apex angle of the convex portion.

[Appendix C31]
Any one of Appendices C23 to C30, wherein the measurement unit measures the riblet structure by comparing data representing the intensity distribution output from the light receiving element with pre-stored reference data of the intensity distribution. 10. The optical device according to claim 1.

[Appendix C32]
A measuring method for measuring a riblet structure based on data representing an intensity distribution output from the optical device according to any one of Appendices C2-C22.

[Appendix C33]
The measuring method according to Appendix C32, wherein the measuring includes calculating a value for the shape of the riblet structure based on the intensity distribution data output from the optical device.

[Appendix C34]
The measuring includes the data of the intensity distribution output from the light receiving element, and a plurality of shape reference data representing the intensity distribution of the light reflected by the irradiation of light to the plurality of riblet structures having different shapes, respectively. C33. The method of measurement of Appendix C33, comprising calculating a value for the shape of the riblet structure based on

[Appendix C35]
The measuring includes inputting the intensity distribution data into a discriminator pretrained to calculate a value for the shape of the riblet structure, thereby outputting a value for the shape of the riblet structure. , appendix C33 or C34.

[Appendix C36]
The measurement method according to Appendix C35, wherein the discriminator comprises a convolutional neural network having a plurality of convolutional layers serially connected from the input side to the output side.

[Appendix C37]
The measuring includes, as the value, at least one of the distance between the convex portions in the second direction, the apex angle of the convex portion, the height of the convex portion, and the radius of curvature of the vertex of the convex portion. A method of measurement according to any one of Appendixes C33-C36, comprising calculating a value representing one.

[Appendix C38]
The light reflected by the irradiation area includes reflected light reflected twice by the convex portion and a region of the irradiation region where the convex portion is not provided,
The reflected light reflected twice includes reflected light reflected from the irradiation area in a first reflection direction and reflected light reflected from the irradiation area in a second reflection direction different from the first reflection direction. including
The measuring is based on the relationship between the incident position of the reflected light reflected in the first reflection direction and the incident position of the reflected light reflected in the second reflection direction on the light receiving surface. A method of measurement according to Appendix C33-C37, comprising calculating a value for the shape of the riblet structure.

[Appendix C39]
The measurement method according to appendix C38, wherein the value relating to the shape of the riblet structure is a value representing the apex angle of the convex portion.

[Appendix C40]
The measuring includes measuring the riblet structure by comparing the intensity distribution data output from the light receiving element with pre-stored intensity distribution reference data. The measurement method according to any one of the items.

[Appendix D1]
A measurement method for measuring a surface to be measured having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
irradiating an irradiation area on the surface to be measured with light;
Condensing the light reflected by the irradiation area by the irradiation of the light with a condensing optical system;
Receiving the condensed light on a surface different from a surface conjugated to the surface to be measured with respect to the condensing optical system;
measuring the riblet structure based on the results of the received light;
including measurement method.

[Appendix D2]
In the light reception, a light-receiving element having a light-receiving surface arranged on a plane different from the conjugate plane receives the condensed light, and the light-receiving element receives the condensed light as a result of the light reception. The measurement method according to appendix D1, which detects an intensity distribution.

[Appendix D3]
The measurement method according to appendix D2, wherein the condensing optical system has a numerical aperture of 0.7 or more on the side of the surface to be measured.

[Appendix D4]
The measurement method according to appendix D2 or D3, wherein the condensing optical system has a numerical aperture of 0.9 or less on the side of the surface to be measured.

[Appendix D5]
The measurement method according to any one of Appendices D2 to D4, wherein the condensing optical system is arranged closest to the surface to be measured and includes a lens member having a concave surface facing the surface to be measured.

[Appendix D6]
further comprising contacting the measurement surface with a contact member that protrudes toward the surface to be measured more than an optical member arranged closest to the surface to be measured among the optical members constituting the condensing optical system; The measurement method according to any one of Appendices D2-D5.

[Appendix D7]
The measurement method according to appendix D6, wherein the contact member contacts at least a part of the surface to be measured excluding the irradiation region.

[Appendix D8]
The contact member and the condensing optical system are configured such that when the contact member contacts the surface to be measured, the condensing optical system and the surface to be measured are arranged in the optical axis direction of the condensing optical system. is the working distance of the condensing optical system on the side of the surface to be measured.

[Appendix D9]
The abutment member has a distance between the converging optical system and the surface to be measured in the optical axis direction of the condensing optical system when the abutting member abuts on the surface to be measured. The measuring method according to any one of Appendices D6 to D8, wherein at least the optical member arranged closest to the surface to be measured is supported so that the working distance of the system is on the side of the surface to be measured.

[Appendix D10]
The light reflected by the irradiation region includes first reflected light reflected once by a region of the irradiation region where the convex portion is not provided, and light reflected by the convex portion and the irradiation region. The measuring method according to any one of Appendices D2 to D9, including the second reflected light reflected twice by the area where the convex portion is not provided.

[Appendix D11]
The condensing optical system reflects at least part of the light from the light source toward the irradiation area, and a part of the first reflected light and the second reflected light that enter the condensing optical system from the irradiation area. D10 according to appendix D10, further comprising a light splitting member configured to transmit reflected light toward the light receiving element and to prevent another part of the first reflected light different from the part from entering the light receiving element. Measuring method.

[Appendix D12]
The measurement method according to appendix D11, wherein the light splitting member reflects the other part of the first reflected light in a direction different from that of the light receiving element.

[Appendix D13]
The light splitting member is configured such that the light amount of the part of the first reflected light emitted from the light splitting member is smaller than the light amount of the other part of the first reflected light emitted from the light splitting member. The measurement method according to appendix D11 or D12.

[Appendix D14]
The condensing optical system according to any one of Appendices D11 to D13, further comprising a lens member disposed closest to the light splitting member when viewed from the surface to be measured and having a concave surface facing the light splitting member. Measurement method described.

[Appendix D15]
The size of the area occupied on the light receiving surface by the light beam incident on the light collecting optical system from one point on the surface to be measured and reaching the light receiving element at the maximum numerical aperture of the light collecting optical system on the side of the surface to be measured , which is 0.1 times or more the size of the light receiving surface.

[Appendix D16]
of Appendices D2 to D15, wherein the light-receiving surface is arranged closer to the exit pupil plane of the light-condensing optical system than an optical member arranged closest to the light-receiving element among the optical members constituting the light-condensing optical system. The measurement method according to any one of the items.

[Appendix D17]
The measurement method according to any one of Appendices D2 to D16, wherein the light receiving surface is arranged on the exit pupil plane of the condensing optical system or on a plane conjugate with the exit pupil.

[Appendix D18]
The measuring method according to any one of Appendices D2 to D17, wherein the convex portion has an inclined surface inclined with respect to a third direction orthogonal to the first direction and the second direction.

[Appendix D19]
The measurement method according to any one of Appendices D2 to D18, wherein the riblet structure is a structure for reducing frictional resistance between the fluid and the surface to be measured.

[Appendix D20]
The optical device according to any one of Appendices D2 to D19, wherein the condensing optical system satisfies the following conditional expression.
γ > β
however,
β: the angle formed between the normal to the end of the effective range of the lens surface closest to the surface to be measured in the condensing optical system and the optical axis of the condensing optical system γ: the condensing optical system the maximum angle formed by the light beam received by the light receiving element among the light beams incident on the lens arranged closest to the surface to be measured and the optical axis of the condensing optical system in

[Appendix D21]
The measurement method according to any one of Appendices D2 to D20, wherein the condensing optical system satisfies the following conditional expression.
y < f sin θ
however,
y: image height of the condensing optical system f: focal length of the condensing optical system θ: angle between the light reflected in the irradiation area and the optical axis of the condensing optical system

[Appendix D22]
The measuring method according to any one of Appendices D2 to D21, wherein the measuring includes measuring the riblet structure based on data representing the intensity distribution output from the light receiving element.

[Appendix D23]
The measuring method according to appendix D22, wherein the measuring includes calculating a value related to the shape of the riblet structure based on the data of the intensity distribution output from the light receiving element.

[Appendix D24]
The measuring includes the data of the intensity distribution output from the light receiving element, and a plurality of shape reference data representing the intensity distribution of the light reflected by the irradiation of light to the plurality of riblet structures having different shapes, respectively. Method of measurement according to appendix D23, comprising calculating a value for the shape of the riblet structure based on

[Appendix D25]
The measuring includes inputting the intensity distribution data into a discriminator pre-trained to calculate a value for the shape of the riblet structure, thereby outputting a value for the shape of the riblet structure. , appendix D23 or D24.

[Appendix D26]
The measurement method according to appendix D25, wherein the discriminator comprises a convolutional neural network having a plurality of convolutional layers serially connected from the input side to the output side.

[Appendix D27]
The measuring includes, as the value, at least one of the distance between the convex portions in the second direction, the apex angle of the convex portion, the height of the convex portion, and the radius of curvature of the vertex of the convex portion. A method of measurement according to any one of appendices D23-D26, comprising calculating a value representing one.

[Appendix D28]
The light reflected by the irradiation area includes reflected light reflected twice by the convex portion and a region of the irradiation region where the convex portion is not provided,
The reflected light reflected twice includes reflected light reflected from the irradiation area in a first reflection direction and reflected light reflected from the irradiation area in a second reflection direction different from the first reflection direction. including
The measuring is based on the relationship between the incident position of the reflected light reflected in the first reflection direction and the incident position of the reflected light reflected in the second reflection direction on the light receiving surface. A method of measurement according to any one of appendices D23-D27, comprising calculating a value for the shape of the riblet structure.

[Appendix D29]
The measurement method according to appendix D28, wherein the value relating to the shape of the riblet structure is a value representing the apex angle of the convex portion.

[Appendix D30]
The measuring includes measuring the riblet structure by comparing the intensity distribution data output from the light receiving element with pre-stored intensity distribution reference data. The measurement method according to any one of the items.

[Appendix D31]
A measuring computer program that causes a computer to execute the measuring method according to any one of Appendices D1-D30.

It should be understood by those skilled in the art that various changes, substitutions and modifications can be made thereto without departing from the spirit and scope of the present disclosure.

REFERENCE SIGNS LIST 1 optical device LS light source 2 condensing optical system 21 lens group 22 light splitting member 3 light receiving element 3a light receiving surface 4 housing 4a contact member 5 computer 531 calculation unit 532 detection unit 533 measurement unit

Claims

An optical device for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
a condensing optical system for irradiating an irradiation area on the surface to be inspected with light from a light source and condensing the light reflected by the irradiation area;
a light-receiving element having a light-receiving surface arranged on a surface different from a surface conjugated to the surface to be inspected with respect to the light-condensing optical system, and detecting an intensity distribution of the light condensed by the light-condensing optical system;
An optical device comprising
The optical device according to claim 1, wherein the condensing optical system has a numerical aperture of 0.7 or more on the inspection surface side.
The optical device according to claim 1 or 2, wherein the condensing optical system has a numerical aperture of 0.9 or less on the inspection surface side.
The optical device according to any one of claims 1 to 3, wherein the condensing optical system includes a lens member arranged closest to the surface to be inspected and having a concave surface facing the surface to be inspected.
further comprising a contact member that protrudes toward the surface to be inspected from an optical member that is arranged closest to the surface to be inspected among the optical members that constitute the condensing optical system, and that is capable of coming into contact with the surface to be inspected. , an optical device according to any one of claims 1-4.
The optical device according to claim 5, wherein the contact member can contact at least a part of the surface to be inspected excluding the irradiation region.
The contact member and the condensing optical system are configured such that when the contact member contacts the surface to be inspected, the condensing optical system and the surface to be inspected are arranged in the optical axis direction of the condensing optical system. 7. The optical device according to claim 5 or 6, arranged so that an interval of is the working distance of the condensing optical system on the side of the surface to be inspected.
The abutment member has a distance between the converging optical system and the surface to be inspected in the optical axis direction of the converging optical system when the abutting member abuts on the surface to be inspected. 8. The optical device according to any one of claims 5 to 7, wherein at least the optical member arranged closest to the surface to be inspected is supported so as to have a working distance of the system on the side of the surface to be inspected.
The light reflected by the irradiation region includes first reflected light reflected once by a region of the irradiation region where the convex portion is not provided, and light reflected by the convex portion and the irradiation region. 9. The optical device according to any one of claims 1 to 8, further comprising a second reflected light reflected twice by a region where the convex portion is not provided.
The condensing optical system reflects at least part of the light from the light source toward the irradiation area, and a part of the first reflected light and the second reflected light that enter the condensing optical system from the irradiation area. 10. The light dividing member according to claim 9, further comprising a light splitting member configured to transmit reflected light toward said light receiving element and prevent the other part of said first reflected light different from said part from entering said light receiving element. optical device.
11. The optical device according to claim 10, wherein said light splitting member reflects said other portion of said first reflected light in a direction different from said light receiving element.
The light splitting member is configured such that the light amount of the part of the first reflected light emitted from the light splitting member is smaller than the light amount of the other part of the first reflected light emitted from the light splitting member. 12. An optical device according to claim 10 or 11, wherein the optical device is
The condensing optical system includes, in order from the surface to be inspected, one or more lens members and the light splitting member, and the one or more lens members are closest to the light splitting member when viewed from the surface to be inspected. 13. The optical device according to any one of claims 10 to 12, further comprising a lens member having a concave surface disposed in and facing the light splitting member.
The size of the area occupied on the light receiving surface by the light beam incident on the light collecting optical system from one point on the surface to be inspected and reaching the light receiving element at the maximum numerical aperture of the light collecting optical system on the side of the surface to be inspected , is at least 0.1 times the size of the light receiving surface.
Claim 1-14, wherein the light-receiving surface is arranged closer to the exit pupil plane of the light-condensing optical system than an optical member arranged closest to the light-receiving element among the optical members constituting the light-condensing optical system. The optical device according to any one of Claims 1 to 3.
The optical device according to any one of claims 1 to 15, wherein the light-receiving surface is arranged on the exit pupil plane of the condensing optical system or on a plane conjugate with the exit pupil.
The optical device according to any one of claims 1 to 16, wherein said convex portion has an inclined surface inclined with respect to a third direction orthogonal to said first direction and said second direction.
The optical device according to any one of claims 1 to 17, wherein the riblet structure is a structure for reducing frictional resistance between the fluid and the surface to be inspected.
The optical device according to any one of claims 1 to 18, further comprising an arithmetic unit that inspects the riblet structure based on data representing the intensity distribution detected by the light receiving element.
20. The optical device according to claim 19, wherein the calculation unit determines the quality of the shape of the convex portion as an inspection of the riblet structure based on the data representing the intensity distribution.
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The calculation unit determines whether the shape of the convex portion is good or bad based on a comparison result between the intensity of the first reflected light incident on the light receiving surface and the intensity of the second reflected light incident on the light receiving surface. 21. The optical device of claim 20, wherein
22. The optical device according to claim 21, wherein the shape of the convex portion includes a rounded vertex of the convex portion.
The light reflected by the irradiation region is divided into first reflected light reflected once by a region of the irradiation region where the convex portion is not provided and the convex portion of the irradiation region. including a second reflected light that is reflected twice by the area not provided and the convex portion;
The second reflected light includes second reflected light reflected in a second reflection direction different from the first reflection direction in which the first reflected light is reflected from the irradiation area, and second reflection light reflected from the irradiation area in the first reflection direction. and a second reflected light reflected in a third reflection direction different from the second reflection direction,
The computing unit calculates the distance between the incident position of the first reflected light on the light receiving surface and the incident position of the second reflected light reflected in the second reflection direction, and the distance between the incident position of the second reflected light on the light receiving surface, 23. The quality of the shape of the convex portion is determined based on the distance between the incident position of the reflected light and the incident position of the second reflected light reflected in the third reflection direction. The optical device according to item 1.
the convex portion has a pair of inclined surfaces that are inclined with respect to a third direction orthogonal to the first direction and the second direction and extend in the first direction;
24. The optical device according to claim 23, wherein the shape of the convex portion includes symmetry between one inclined surface and the other inclined surface of the pair of inclined surfaces.
The computing unit includes data representing the intensity distribution detected by the light-receiving element, at least one non-defective product reference data representing the intensity distribution of light reflected by irradiation of light to the convex portion of the shape of a non-defective product, and non-defective product standard data. Determining the quality of the shape of the convex portion by comparing with at least one of at least one of the defective product reference data representing the intensity distribution of the light reflected by the irradiation of light to the convex portion of the shape of the non-defective product. Optical device according to any one of claims 20-24.
The computing unit inputs the data representing the intensity distribution detected by the light receiving element to a classifier pre-learned to determine the quality of the shape of the convex portion, thereby determining the shape of the convex portion. 26. The optical device according to any one of claims 20 to 25, which determines the quality of the optical device.
The optical device according to any one of claims 20 to 26, wherein said calculation unit calculates a value related to the shape of said convex portion based on data representing said intensity distribution detected by said light receiving element.
An inspection method for inspecting a riblet structure based on data representing the intensity distribution detected by the optical device according to any one of claims 1-18.
An inspection method for inspecting a surface to be inspected having a riblet structure in which a plurality of convex portions extending in a first direction are provided in a second direction intersecting the first direction,
irradiating an irradiation area on the surface to be inspected with light;
Condensing the light reflected by the irradiation area by the irradiation of the light with a condensing optical system;
Receiving the condensed light on a plane different from a plane conjugated to the surface to be inspected with respect to the condensing optical system;
inspecting the riblet structure based on the results of receiving light;
inspection methods including;